Self-assembling protein nanostructures displaying paramyxovirus and/or pneumovirus F proteins and their use

ABSTRACT

Disclosed herein are nanostructures and their use, where the nanostructures include (a) a plurality of first assemblies, each first assembly comprising a plurality of identical first polypeptides; (b) a plurality of second assemblies, each second assembly comprising a plurality of identical second polypeptides, wherein the second polypeptide differs from the first polypeptide; wherein the plurality of first assemblies non-covalently interact with the plurality of second assemblies to form a nanostructures; and wherein the nanostructure displays multiple copies of one or more paramyxovirus and/or pneumovirus F proteins or antigenic fragments thereof, on an exterior of the nanostructure.

CROSS REFERENCE

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 62/481,331 filed Apr. 4, 2017, incorporated by reference hereinin its entirety

BACKGROUND

Molecular self- and co-assembly of proteins into highly ordered,symmetric supramolecular complexes is an elegant and powerful means ofpatterning matter at the atomic scale. Recent years have seen advancesin the development of self-assembling biomaterials, particularly thosecomposed of nucleic acids. DNA has been used to create, for example,nanoscale shapes and patterns, molecular containers, andthree-dimensional macroscopic crystals. Methods for designingself-assembling proteins have progressed more slowly, yet the functionaland physical properties of proteins make them attractive as buildingblocks for the development of advanced functional materials.

SUMMARY OF THE INVENTION

In one aspect, nanostructures are provided comprising:

(a) a plurality of first assemblies, each first assembly comprising aplurality of identical first polypeptides;

(b) a plurality of second assemblies, each second assembly comprising aplurality of identical second polypeptides, wherein the secondpolypeptide differs from the first polypeptide;

wherein the plurality of first assemblies non-covalently interact withthe plurality of second assemblies to form a nanostructure; and

wherein the nanostructure displays multiple copies of one or moreparamyxovirus and/or pneumovirus F proteins, or antigenic fragmentsthereof, on an exterior of the nanostructure.

In one embodiment, (a) the first polypeptides comprise a polypeptidehaving at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93% 94% 95% 96%, 97%,98%, 99%, or 100% identity along its full length to the amino acidsequence of a polypeptide selected from the group consisting of SEQ IDNOS:1-51; and

(b) the second polypeptides comprise a polypeptide having at least 70%,75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%identity along its full length to the amino acid sequence of apolypeptide selected from the group consisting of SEQ ID NOS:1-51.

In another embodiment, the one or more paramyxovirus and/or pneumovirusF proteins, or antigenic fragments thereof, comprise a polypeptidehaving at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%,98%, 99%, or 100% identity along its full length to the amino acidsequence of a polypeptide selected from the group consisting of SEQ IDNOS: 53, 61-68, and 101.

In various embodiments:

(a) the first polypeptide comprises a polypeptide having at least 75%,80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%identity along its full length to the amino acid sequence of T33-31A(SEQ ID NO:51) and the second polypeptide comprises a polypeptide havingat least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%,99%, or 100% identity along its full length to the amino acid sequenceof T33-09B/T33-31B (SEQ ID NO:44);

(b) the first polypeptide comprises a polypeptide having at least 75%,80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%identity along its full length to the amino acid sequence of T33-15B(SEQ ID NO:46) and the second polypeptide comprises a polypeptide havingat least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%,99%, or 100% identity along its full length to the amino acid sequenceof T33-15A (SEQ ID NO:45);

(c) the first polypeptide has at least 75%, 80%, 85%, 90%, 91%, 92%,93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity along its fulllength to the amino acid sequence of a polypeptide selected from thegroup consisting of I53-50A (SEQ ID NO:7), I53-50A.1 (SEQ ID NO:29),I53-50A.1NegT2 (SEQ ID NO:30), and I53-50A.1PosT1 (SEQ ID NO:31), andthe second polypeptide has at least 75%, 80%, 85%, 90%, 91%, 92%, 93%,94%, 95%, 96%, 97%, 98%, 99%, or 100% identity along its full length tothe amino acid sequence of a polypeptide selected from the groupconsisting of I53-50B (SEQ ID NO:8), I53-50B.1 (SEQ ID NO:32),I53-50B.1NegT2 (SEQ ID NO:33), and I53-50B.4PosT1 (SEQ ID NO:34); or

(d) the first polypeptide comprises a polypeptide having at least 75%,80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%identity along its full length to the amino acid sequence of I32-28A(SEQ ID NO:21) and the second polypeptide comprises a polypeptide havingat least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%,99%, or 100% identity along its full length to the amino acid sequenceof I32-28B (SEQ ID NO:22).

In one embodiment, the one or more paramyxovirus and/or pneumovirus Fproteins, or antigenic fragments thereof, are expressed as a fusionprotein with the first polypeptides. In one such embodiment, theplurality of first assemblies each comprise identical firstpolypeptides; in another such embodiment, the plurality of firstassemblies in total comprise two or more paramyxovirus and/orpneumovirus F proteins, or antigenic fragments thereof. In anotherembodiment, only a subset of the first polypeptides comprise a fusionprotein with an F protein or antigenic fragment thereof. In a furtherembodiment, each first assembly comprises a homotrimer of the firstpolypeptide.

In another embodiment, the fusion protein comprises an amino acid linkerpositioned between the first polypeptide and the paramyxovirus and/orpneumovirus F proteins, or antigenic fragment thereof. In one suchembodiment, the fusion protein comprises an amino acid linker positionedbetween the first polypeptide and the paramyxovirus F proteins, orantigenic fragment thereof.

In one embodiment the amino acid linker sequence comprises one or moretrimerization domain; in another embodiment the amino acid linkersequence comprises a Gly-Ser linker.

In various embodiments, the first polypeptides comprise or consist offirst polypeptides having at least 75%, 80%, 85%, 90%, 91%, 92%, 93%,94%, 95%, 96%, 97%, 98%, 99%, or 100% identity along their full lengthto the amino acid sequence of a polypeptide selected from the groupconsisting of DS-Cav1-foldon-T33-31A (SEQ ID NO:69), DS-Cav1-T33-31A(SEQ ID NO:70), DS-Cav1-foldon-T33-15B (SEQ ID NO:71), DS-Cav1-T33-15B(SEQ ID NO:72), DS-Cav1-foldon-I53-50A (SEQ ID NO:73), DS-Cav1-I53-50A(SEQ ID NO:74), and DS-Cav1-I32-28A (SEQ ID NO:75).

In other embodiments,

(a) when each first polypeptide has at least 75%, 80%, 85%, 90%, 91%,92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity along its fulllength to the amino acid sequence of DS-Cav1-foldon-T33-31A (SEQ IDNO:69) or DS-Cav1-T33-31A (SEQ ID NO:70), each second polypeptide has atleast 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%,or 100% identity along its full length to the amino acid sequence ofT33-31B (SEQ ID NO:44);

(b) when each first polypeptide has at least 75%, 80%, 85%, 90%, 91%,92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity along its fulllength to the amino acid sequence of DS-Cav1-foldon-T33-15B (SEQ IDNO:71) or DS-Cav1-T33-15B (SEQ ID NO:72), each second polypeptide has atleast 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%,or 100% identity along its full length to the amino acid sequence ofT33-15A (SEQ ID NO:45);

(c) when each first polypeptide has at least 75%, 80%, 85%, 90%, 91%,92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity along its fulllength to the amino acid sequence of DS-Cav1-foldon-I53-50A (SEQ IDNO:73) or DS-Cav1-I53-50A (SEQ ID NO:74), each second polypeptide has atleast 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%,or 100% identity along its full length to the amino acid sequence of apolypeptide selected from the group consisting of 53-50B (SEQ ID NO:8),I53-50B.1 (SEQ ID NO:32), I53-50B.1NegT2 (SEQ ID NO:33), orI53-50B.4PosT1 (SEQ ID NO:34); or

(d) when each first polypeptide has at least 75%, 80%, 85%, 90%, 91%,92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity along its fulllength to the amino acid sequence of DS-Cav1-I32-28A (SEQ ID NO:75),each second polypeptide has at least 75%, 80%, 85%, 90%, 91%, 92%, 93%,94%, 95%, 96%, 97%, 98%, 99%, or 100% identity along its full length tothe amino acid sequence of 132-28B.

In one embodiment, the one or more paramyxovirus and/or pneumovirus Fproteins, or antigenic fragments thereof comprises a polypeptide havingat least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%,99%, or 100% identity along its full length to the amino acid sequenceof DS-Cav1(SEQ ID NO:53). In one such embodiment, each first polypeptidecomprises a fusion polypeptide of a polypeptide having at least 75%,80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%identity along its full length to the amino acid sequence of DS-Cav1linked via an amino acid linker to a polypeptide having at least 75%,80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%identity along its full length to the amino acid sequence of SEQ ID NO:7(I53-50A). In another embodiment, the amino acid linker comprises aGly-Ser linker. In a further embodiment, each fusion protein comprises apolypeptide having at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%,96%, 97%, 98%, 99%, or 100% identity along its full length to the aminoacid sequence selected from the group consisting of SEQ ID NOS:69-100.In a specific embodiment, each fusion protein comprises a polypeptidehaving at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%,98%, 99%, or 100% identity along its full length to the amino acidsequence of SEQ ID NO:76 (F10). In other embodiments, each secondpolypeptide comprises a polypeptide having at least 75%, 80%, 85%, 90%,91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity along itsfull length to the amino acid sequence selected from the groupconsisting of 153-50B (SEQ ID NO:8), I53-50B.1 (SEQ ID NO:32),I53-50B.1NegT2 (SEQ ID NO:33), or I53-50B.4PosT1 (SEQ ID NO:34). In aspecific embodiment, each second polypeptide comprises a polypeptidehaving at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%,98%, 99%, or 100% identity along its full length to the amino acidsequence of I53-50B.4PosT1 (SEQ ID NO:34).

In other aspects, recombinant expression nucleic acids expressing thefirst polypeptide fusions, recombinant expression vectors comprising therecombinant nucleic acids linked to a promoter, and recombinant hostcells comprising the recombinant expression vectors are provided.

Also provided are immunogenic compositions comprising the nanostructureof any embodiment or combination of embodiments disclosed herein, and apharmaceutically acceptable carrier. In one embodiment, the immunogeniccompositions may further comprise an adjuvant.

In other aspects, methods for generating an immune response to RSV Fprotein in a subject, or for treating or limiting a RSV infection in asubject are provided, comprising administering to the subject in needthereof an effective amount of the nanostructure or immunogeniccomposition of embodiment or combination of embodiments disclosed hereinto generate the immune response or to treat or prevent RSV infection inthe subject.

Also provided are processes assembling the nanostructures of anyembodiment or combination of embodiments disclosed herein, comprisingmixing two or more nanostructures components in aqueous conditions todrive spontaneous assembly of the desired nanostructures.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention will become more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings.

FIG. 1 shows a schematic diagram of the production of antigen-bearingnanostructures by in vitro assembly. The two components or buildingblocks of a given nanostructure can be expressed and purifiedindividually, which allows assembly of the nanostructure to be initiatedby mixing the purified components in vitro, a process referred to as invitro assembly. In some embodiments, the two components of thenanostructure may be expressed in different expression hosts (e.g.,human HEK293F cells or bacterial E. coli cells). The figureschematically depicts assembly of a 120-subunit nanostructure bearing 20trimeric antigens (60 antigen subunits) via in vitro assembly of anantigen-nanostructure trimer fusion protein produced in HEK293F cellsand a nanostructure pentamer protein produced in E. coli.

FIG. 2 shows graphs illustrating detection of secreted DS-Cav1,DS-Cav1-foldon-T33-31A, and DS-Cav1-T33-31A fusion proteins in tissueculture supernatants. ELISA assays were performed on tissue culturesupernatants from cells expressing DS-Cav1 (top),DS-Cav-1-foldon-T33-31A/T33-31B (bottom left), andDS-Cav-1-T33-31A/T33-31B (bottom right). Four different monoclonalantibodies that bind RSV F were used to evaluate the presence of DS-Cav1or DS-Cav1 fusion proteins in the supernatants. The results confirm thesecretion of proteins comprising well-folded RSV F antigen.

FIG. 3 shows size-exclusion chromatography of DS-Cav1-I53-50A. Proteinpurified from tissue culture supernatants by immobilized metal affinitychromatography was applied to a Superose™ 6 10/300 GL size exclusioncolumn. The protein eluted as a single, monodisperse species.

FIG. 4 shows size exclusion chromatography of in vitro-assembledDS-Cav1-153-50 nanostructures. Purified DS-Cav1-I53-50A and 153-50B.4PT1proteins were mixed at an approximately 1:1 molar ratio, incubatedovernight at 4° C., and then applied to a Sephacryl S-500 16/60 HR sizeexclusion column. The assembled nanostructure eluted as a single,monodisperse peak around 65 mL, while excess DS-Cav1-I53-50A trimericcomponent eluted around 90 mL.

FIG. 5 shows a negative stain electron micrograph and two-dimensionalclass averages of in vitro-assembled DS-Cav1-I53-50 nanostructures. Invitro-assembled DS-Cav1-I53-50 nanostructures, purified by sizeexclusion chromatography, were imaged by negative stain electronmicroscopy (top). Averaging many nanostructures yielded two-dimensionalclass averages (bottom) that indicate that the I53-50 portion of thenanostructures is highly ordered and consistent, while the precisethree-dimensional position of the displayed antigen varies slightly dueto the flexible nature of the linker between the DS-Cav1 and I53-50Adomains of the DS-Cav1-I53-50A fusion protein.

FIG. 6 shows a series of graphs depicting the antigenicity ofDS-Cav1-I53-50 nanostructures. Analysis of purified DS-Cav1-I53-50nanostructures by ELISA (A) using four RSV F-specific monoclonalantibodies, including the prefusion-specific antibodies MPE8, D25, andRSD5, indicated that the DS-Cav1 antigen is correctly folded andmaintained in the prefusion state when multivalently displayed onDS-Cav1-I53-50 nanostructures. This finding was confirmed by surfaceplasmon resonance measurements using multiple RSV F-specific antibodies(B-C), which, when compared to trimeric DS-Cav1, further suggested thatmultivalent display of DS-Cav1 results in an avidity effect that reducesthe dissociation rate of the antibodies.

FIG. 7 is a graph depicting DS-Cav1-specific serum antibody titers frommice immunized with DS-Cav1-I53-50 nanostructures. Groups of mice wereimmunized with I53-50 nanostructures lacking additional antigen,trimeric DS-Cav1, or I53-50 nanostructures bearing DS-Cav1 antigen at33%, 66%, or 100% valency. DS-Cav1-specific serum antibody titers weremeasured by ELISA on plates coated with DS-Cav1. Serum antibody titersfor each mouse are plotted as circles, with the geometric mean withineach group plotted as a horizontal line.

FIG. 8 is a graph depicting serum neutralization activity elicited byimmunization with DS-Cav1-I53-50 nanostructures. Groups of mice wereimmunized with I53-50 nanostructures lacking additional antigen,trimeric DS-Cav1, or I53-50 nanostructures bearing DS-Cav1 antigen at33%, 66%, or 100% valency. Neutralization titers for each mouse areplotted as circles, with the geometric mean within each group plotted asa horizontal line.

FIG. 9 is a graph depicting immunogenicity in a primate immune systemelicited by immunization with DS-Cav1-foldon I53-50 nanostructures.Rhesus macaques were injected at weeks 0 and 4 with either free DS-Cav1trimer or DS-Cav1-foldon-I53-50 nanostructures displaying DS-Cav1 at100% valency. In both cases, the dose of DS-Cav1 antigen was 50 μg, andthe immunogens were formulated with the MF59-like, squalene-basedoil-in-water emulsion adjuvant SWE. Sera obtained from the animals atweeks 6 and 16 were evaluated for anti-DS-Cav1 antibody titers (A) andRSV-neutralizing antibody titers (B).

FIG. 10 is a graph depicting the physical stability of DS-Cav1 whenfused to I53-50A and/or when further assembled into the icosahedralnanostructure. Samples of trimeric DS-Cav1, trimericDS-Cav1-foldon-I53-50A, and DS-Cav1-foldon-I53-50 nanostructurescontaining equivalent concentrations of DS-Cav1 were split into fouraliquots and incubated at 20, 50, 70 or 80° C. for 1 hour. After coolingto room temperature, D25 binding was assayed by surface plasmonresonance (SPR).

FIG. 11 is a graph depicting physical stability of the nanostructures.Chemical denaturation in guanidine hydrochloride (GdnHCl), monitored byintrinsic tryptophan fluorescence, was used as a second,antibody-independent technique to evaluate physical stability oftrimeric DS-Cav1 (A-B), DS-Cav1-foldon-I53-50A (C-D),DS-Cav1-foldon-I53-50 (E-F), 153-50 (G-H), and I53-50A (I-J). The dataindicate superior physical stability of the DS-Cav1 antigen whengenetically fused to the 153-50A nanostructure component.

DETAILED DESCRIPTION OF THE INVENTION

All references cited are herein incorporated by reference in theirentirety. Within this application, unless otherwise stated, thetechniques utilized may be found in any of several well-known referencessuch as: Molecular Cloning: A Laboratory Manual (Sambrook, et al., 1989,Cold Spring Harbor Laboratory Press), Gene Expression Technology(Methods in Enzymology, Vol. 185, edited by D. Goeddel, 1991. AcademicPress, San Diego, Calif.), “Guide to Protein Purification” in Methods inEnzymology (M. P. Deutshcer, ed., (1990) Academic Press, Inc.); PCRProtocols: A Guide to Methods and Applications (Innis, et al. 1990.Academic Press, San Diego, Calif.), Culture of Animal Cells: A Manual ofBasic Technique, 2^(nd) Ed. (R. I. Freshney, 1987. Liss, Inc. New York,N.Y.), Gene Transfer and Expression Protocols, pp. 109-128, ed. E. J.Murray, The Humana Press Inc., Clifton, N.J.), and the Ambion 1998Catalog (Ambion, Austin, Tex.).

As used herein, the singular forms “a”, “an” and “the” include pluralreferents unless the context clearly dictates otherwise. “And” as usedherein is interchangeably used with “or” unless expressly statedotherwise.

As used herein, the amino acid residues are abbreviated as follows:alanine (Ala; A), asparagine (Asn; N), aspartic acid (Asp; D), arginine(Arg; R), cysteine (Cys; C), glutamic acid (Glu; E), glutamine (Gln; Q),glycine (Gly; G), histidine (His; H), isoleucine (Ile; I), leucine (Leu;L), lysine (Lys; K), methionine (Met; M), phenylalanine (Phe; F),proline (Pro; P), serine (Ser; S), threonine (Thr; T), tryptophan (Trp;W), tyrosine (Tyr; Y), and valine (Val; V).

As used herein, “about” means +/−5% of the recited parameter.

All embodiments of any aspect of the invention can be used incombination, unless the context clearly dictates otherwise.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words ‘comprise’, ‘comprising’, and thelike are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to”. Words using the singular or pluralnumber also include the plural and singular number, respectively.Additionally, the words “herein,” “above,” and “below” and words ofsimilar import, when used in this application, shall refer to thisapplication as a whole and not to any particular portions of theapplication.

The description of embodiments of the disclosure is not intended to beexhaustive or to limit the disclosure to the precise form disclosed.While the specific embodiments of, and examples for, the disclosure aredescribed herein for illustrative purposes, various equivalentmodifications are possible within the scope of the disclosure, as thoseskilled in the relevant art will recognize.

In a first aspect, the disclosure provides nanostructures, comprising:

(a) a plurality of first assemblies, each first assembly comprising aplurality of identical first polypeptides;

(b) a plurality of second assemblies, each second assembly comprising aplurality of identical second polypeptides, wherein the secondpolypeptide differs from the first polypeptide;

wherein the plurality of first assemblies non-covalently interact withthe plurality of second assemblies to form a nanostructure; and

wherein the nanostructure displays multiple copies of one or moreparamyxovirus and/or pneumovirus F proteins, or antigenic fragmentsthereof, on an exterior of the nanostructure.

Self-assembling polypeptide nanostructures are disclosed herein thatmultivalently display paramyxovirus and/or pneumovirus F proteins on thenanostructure exteriors. Multiple copies of pairs of first and secondpolypeptides are able to self-assemble to form nanostructures, such asicosahedral nanostructures. The nanostructures include symmetricallyrepeated, non-natural, non-covalent polypeptide-polypeptide interfacesthat orient a first assembly and a second assembly into a nanostructure,such as one with an icosahedral symmetry.

The nanostructures of the invention are synthetic, in that they are notnaturally occurring. The first polypeptides and the second polypeptidesare non-naturally occurring proteins that can be produced by anysuitable means, including recombinant production or chemical synthesis.Each member of the plurality of first polypeptides is identical to eachother (though when the first polypeptide is present as a fusionpolypeptide with one or more paramyxovirus and/or pneumovirus Fproteins, or antigenic fragments thereof, the F protein or antigenicfragment thereof may differ from one first polypeptide to another), andeach member of the plurality of second polypeptides is identical to eachother. The first proteins and the second proteins are different. Thereare no specific primary amino acid sequence requirements for the firstand second polypeptides. US published patent application 20160122392 andpublished PCT application WO2014/124301 describe methods for designingsynthetic nanostructures, where the nanostructures are not dependent onspecific primary amino acid sequences of the first and secondpolypeptides.

A plurality (2, 3, 4, 5, 6, or more) of first polypeptides self-assembleto form a first assembly, and a plurality (2, 3, 4, 5, 6, or more) ofsecond polypeptides self-assemble to form a second assembly. A pluralityof these first and second assemblies then self-assemble non-covalentlyvia the designed interfaces to produce the nanostructures.

The number of first polypeptides in the first assemblies may be the sameor different than the number of second polypeptides in the secondassemblies. In one exemplary embodiment, the first assembly comprisestrimers of the first polypeptides, and the second assembly comprisesdimers of the second polypeptides. In a further exemplary embodiment,the first assembly comprises trimers of the first polypeptides, and thesecond assembly comprises trimers of the second polypeptides. In afurther exemplary embodiment, the first assembly comprises trimers ofthe first polypeptides, and the second assembly comprises pentamers ofthe second polypeptides.

The first and second polypeptides may be of any suitable length for agiven purpose of the resulting nanostructure. In one embodiment, thefirst polypeptides and the second polypeptides are typically between30-250 amino acids in length; the length of the first polypeptides andthe second polypeptides may be the same or different. In various furtherembodiments, the first polypeptides and the second polypeptides arebetween 30-225, 30-200, 30-175, 50-250, 50-225, 50-200, 50-175, 75-250,75-225, 75-200, 75-175, 100-250, 100-225, 100-200, 100-175, 125-250,125-225, 125-200, 125-175, 150-250, 150-225, 150-200, and 150-175 aminoacids in length.

The isolated polypeptides of SEQ ID NOS:1-51 were designed for theirability to self-assemble in pairs to form nanostructures, such asicosahedral nanostructures. The design involved design of suitableinterface residues for each member of the polypeptide pair that can beassembled to form the nanostructure. The nanostructures so formedinclude symmetrically repeated, non-natural, non-covalentpolypeptide-polypeptide interfaces that orient a first assembly and asecond assembly into a nanostructure, such as one with an icosahedralsymmetry. Thus, in one embodiment the first and second polypeptides areselected from the group SEQ ID NOS:1-51. In each case, the N-terminalmethionine residue is optional.

TABLE 1 Name Amino Acid Sequence Identified interface residues I53-34A(M)EGMDPLAVLAESRLLPLLTVRGGEDLAGLATVLELMGV I53-34A: SEQ ID NO: 1GALEITLRTEKGLEALKALRKSGLLLGAGTVRSPKEAEAAL28, 32, 36, 37, 186, 188, 191, EAGAAFLVSPGLLEEVAALAQARGVPYLPGVLTPTEVERAL 192, 195ALGLSALKFFPAEPFQGVRVLRAYAEVFPEVRFLPTGGIKEEHLPHYAALPNLLAVGGSWLLQGDLAAVMKKVKAAKALLSP QAPG I53-34B(M)TKKVGIVDTTFARVDMAEAAIRTLKALSPNIKIIRKTV I53-34B: SEQ ID NO: 2PGIKDLPVACKKLLEEEGCDIVMALGMPGKAEKDKVCAHEA 19, 20, 23, 24, 27, 109, 113, SLGLMLAQLMTNKHIIEVFVHEDEAKDDDELDILALVRAIE 116, 117, 120, 124, 148HAANVYYLLFKPEYLTRMAGKGLRQGREDAGPARE I53-40A(M)TKKVGIVDTTFARVDMASAAILTLKMESPNIKIIRKTV I53-40A: SEQ ID NO: 3PGIKDLPVACKKLLEEEGCDIVMALGMPGKAEKDKVCAHEA 20, 23, 24, 27, 28, 109, 112, SLGLMLAQLMTNKHIIEVFVHEDEAKDDAELKILAARRAIE 113, 116, 120, 124HALNVYYLLFKPEYLTRMAGKGLRQGFEDAGPARE I53-40B(M)STINNQLKALKVIPVIAIDNAEDIIPLGKVLAENGLPA I53-40B: SEQ ID NO: 4AEITFRSSAAVKAIMLLRSAQPEMLIGAGTILNGVQALAAK 47, 51, 54, 58, 74, 102EAGATFVVSPGFNPNTVRACQIIGIDIVPGVNNPSTVEAALEMGLTTLKFFPAEASGGISMVKSLVGPYGDIRLMPTGGITPSNIDNYLAIPQVLACGGTWMVDKKLVTNGEWDEIARLTREI VEQVNP I53-47A(M)PIFTLNTNIKATDVPSDFLSLTSRLVGLILSKPGSYVA I53-47A: SEQ ID NO: 5VHINTDQQLSFGGSTNPAAFGTLMSIGGIEPSKNRDHSAVL 22, 25, 29, 72, 79, 86, 87EDHLNAMLGIPKNRMYIHFVNLNGDDVGWNGTTF I53-47B(M)NQHSHKDYETVRIAVVRARWHADIVDACVEAFEIAMAA I53-47B: SEQ ID NO: 6IGGDRFAVDVFDVPGAYIEPLHARTLAETGRYGAVLGTAFV 28, 31, 35, 36, 39, 131, 132, VNGGIYRHEFVASAVIDGMMNVQLSTGVPVLSAVLTPHRYR 135, 139, 146DSAEHHRFFAAHFAVKGVEAARACIEILAAREKIAA I53-50A(M)KMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLI I53-50A: SEQ ID NO: 7EITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAV 25, 29, 33, 54, 57ESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGC TE I53-50B(M)NQHSHKDYETVRIAVVRARWHAEIVDACVSAFEAAMAD I53-50B: SEQ ID NO: 8IGGDRFAVDVFDVPGAYEIPLHARTLAETGRYGAVLGTAFV24, 28, 36, 124, 125, 127, 128, VNGGIYRHEFVASAVIDGMMNVQLSTGVPVLSAVLTPHRYR 129, 131, 133, 133, 135, 139DSDAHTLLFLALFAVKGMEAARACVEILAAREKIAA I53-51A(M)FTKSGDDGNTNVINKRVGKDSPLVNFLGDLDELNSFIG I53-51A: SEQ ID NO: 9FAISKIPWEDMKKDLERVQVELFEIGEDLSTQSSKKKIDES80, 83, 86, 87, 88, 90, 91, 94, YVLWLLAATAIYRIESGPVKLFVIPGGSEEASVLHVTRSVA 166, 172, 176RRVERNAVKYTKELPEINRMIIVYLNRLSSLLFAMALVANK RRNQSEKIYEIGKSW I53-51B(M)NQHSHKDYETVRIAVVRARWHADIVDQCVRAFEEAMAD I53-51B: SEQ ID NO: 10AGGDRFAVDVFDVPGAYEIPLHARTLAETGRYGAVLGTAFV31, 35, 36, 40, 122, 124, 128, VNGGIYRHEFVASAVIDGMMNVQLSTGVPVLSAVLTPHRYR 131, 135, 139, 143, 146, 147SSREHHEFFREHFMVKGVEAAAACITILAAREKIAA I52-03A(M)GHTKGPTPQQHDGSALRIGIVHARWNKTIIMPLLIGTI I52-03A: SEQ ID NO: 11AKLLECGVKASNIVVQSVPGSWELPIAVQRLYSASQLQTPS 28, 32, 36, 39, 44, 49SGPSLSASDLLGSSTTDLTALPTTTASSTGPFDALIAIGVLIKGETMHFEYIADSVSHGLMRVQLDTGVPVIFGVLTVLTDDQAKARAGVIEGSHNHGEDWGLAAVEMGVRRRDWAAGKTE I52-03B(M)YEVDHADVYDLFYLGRGKDYAAEASDIADLVRSRTPEA I52-03B: SEQ ID NO: 12SSLLDVACGTGTHLEHFTKEFGDTAGLELSEDMLTHARKRL 94, 115, 116, 206, 213PDATLHQGDMRDFQLGRKFSAVVSMFSSVGYLKTVAELGAAVASFAEHLEPGGVVVVEPWWFPETFADGWVSADVVRRDGRTVARVSHSVREGNATRMEVHFTVADPGKGVRHFSDVHLITLFHQREYEAAFMAAGLRVEYLEGGPSGRGLFVGVPA I52-32A(M)GMKEKFVLIITHGDFGKGLLSGAEVIIGKQENVHTVGL I52-32A: SEQ ID NO: 13NLGDNIEKVAKEVMRIIIAKLAEDKEIIIVVDLFGGSPFNI47, 49, 53, 54, 57, 58, 61, 83, ALEMMKTFDVKVITGINMPMLVELLTSINVYDTTELLENIS 87, 88 KIGKDGIKVIEKSSLKMI52-32B (M)KYDGSKLRIGILHARWNLEIIAALVAGAIKRLQEFGVK I52-32B: SEQ ID NO: 14AENIIIETVPGSFELPYGSKLFVEKQKRLGKPLDAIIPIGV 19, 20, 23, 30, 40LIKGSTMHFEYICDSTTHQLMKLNFELGIPVIFGVLTCLTDEQAEARAGLIEGKMHNHGEDWGAAAVEMATKFN I52-33A(M)AVKGLGEVDQKYDGSKLRIGILHARWNRKIILALVAGA I52-33A: SEQ ID NO: 15VLRLLEFGVKAENIIIETVPGSFELPYGSKLFVEKQKRLGK 33, 41, 44, 50PLDAIIPIGVLIKGSTMHFEYICDSTTHQLMKLNFELGIPVIFGVLTCLTDEQAEARAGLIEGKMHNHGEDWGAAAVEMATK FN I52-33B(M)GANWYLDNESSRLSFTSTKNADIAEVHRFLVLHGKVDP I52-33B: SEQ ID NO: 16KGLAEVEVETESISTGIPLRDMLLRVLVFQVSKFPVAQINA 61, 63, 66, 67, 72, 147, 148, QLDMRPINNLAPGAQLELRLPLTVSLRGKSHSYNAELLATR 154, 155LDERRFQVVTLEPLVIHAQDFDMVRAFNALRLVAGLSAVSL SVPVGAVLIFTAR I32-06A(M)TDYIRDGSAIKALSFAIILAEADLRHIPQDLQRLAVRV I32-06A: SEQ ID NO: 17IHACGMVDVANDLAFSEGAGKAGRNALLAGAPILCDARMVA 9, 12, 13, 14, 20, 30, 33, 34EGITRSRLPADNRVIYTLSDPSVPELAKKIGNTRSAAALDLWLPHIEGSIVAIGNAPTALFRLFELLDAGAPKPALIIGMPVGFVGAAESKDELAANSRGVPYVIVRGRRGGSAMTAAAVNAL ASERE I32-06B(M)ITVFGLKSKLAPRREKLAEVIYSSLHLGLDIPKGKHAI I32-06B: SEQ ID NO: 18RFLCLEKEDFYYPFDRSDDYTVIEINLMAGRSEETKMLLIF24, 71, 73, 76, 77, 80, 81, 84, LLFIALERKLGIRAHDVEITIKEQPAHCWGFRGRTGDSARD 85, 88, 114, 118 LDYDIYVI32-19A (M)GSDLQKLQRFSTCDISDGLLNVYNIPTGGYFPNLTAIS I32-19A: SEQ ID NO: 19PPQNSSIVGTAYTVLFAPIDDPRPAVNYIDSVPPNSILVLA 3, 4, 6, 7, 9, 10, 25, 27, 36,LEPHLQSQFHPFIKITQAMYGGLMSTRAQYLKSNGTVVFGR40, 42, 43, 44, 49, 58, 59, 61,IRDVDEHRTLNHPVFAYGVGSCAPKAVVKAVGTNVQLKILT62, 63, 70, 72, 73, 74, 82, 84,SDGVTQTICPGDYIAGDNNGIVRIPVQETDISKLVTYIEKS88, 89, 109, 110, 112, 126, 127, IEVDRLVSEAIKNGLPAKAAQTARRMVLKDYI129, 130, 132, 146, 155, 156, 157, 159, 166, 169, 172, 189,190, 192, 194, 195, 198, 201, 204, 215, 232 I32-19B(M)SGMRVYLGADHAGYELKQAIIAFLKMTGHEPIDCGALR I32-19B: SEQ ID NO: 20YDADDDYPAFCIAAATRTVADPGSLGIVLGGSGNGEQIAAN 20, 23, 24, 27, 117, 118, 122,KVPGARCALAWSVQTAALAREHNNAQLIGIGGRMHTLEEAL 125RIVKAFVTTPWSKAQRHQRRIDILAEYERTHEAPPVPGAPA I32-28A(M)GDDARIAAIGDVDELNSQIGVLLAEPLPDDVRAALSAI I32-28A: SEQ ID NO: 21QHDLFDLGGELCIPGHAAITEDHLLRLALWLVHYNGQLPPL 60, 61, 64, 67, 68, 71, 110,EEFILPGGARGAALAHVCRTVCRRAERSIKALGASEPLNIA 120, 123, 124, 128PAAYVNLLSDLLFVLARVLNRAAGGADVLWDRTRAH I32-28B(M)ILSAEQSFTLRHPHGQAAALAFVREPAAALAGVQRLRG I32-28B: SEQ ID NO: 22LDSDGEQVWGELLVRVPLLGEVDLPFRSEIVRTPQGAELRP35, 36, 54, 122, 129, 137, 140,LTLTGERAWVAVSGQATAAEGGEMAFAFQFQAHLATPEAEG 141, 144, 148EGGAAFEVMVQAAAGVTLLLVAMALPQGLAAGLPPA I53-40A.1(M)TKKVGIVDTTFARVDMASAAILTLKMESPNIKIIRKTV I53-40A: SEQ ID NO: 23PGIKDLPVACKKLLEEEGCDIVMALGMPGKKEKDKVCAHEA 20, 23, 24, 27, 28, 109, 112,SLGLMLAQLMTNKHIIEVFVHEDEAKDDAELKILAARRAIE 113, 116, 120, 124HALNVYYLLFKPEYLTRMAGKGLRQGFEDAGPARE I53-40B.1(M)DDINNQLKRLKVIPVIAIDNAEDIIPLGKVLAENGLPA I53-40B: SEQ ID NO: 24AEITFRSSAAVKAIMLLRSAQPEMLIGAGTILNGVQALAAK 47, 51, 54, 58, 74, 102EAGADFVVSPGFNPNTVRACQIIGIDIVPGVNNPSTVEQALEMGLTTLKFFPAEASGGISMVKSLVGPYGDIRLMPTGGITPDNIDNYLAIPQVLACGGTWMVDKKLVRNGEWDEIARLTREI VEQVNP I53-47A.1(M)PIFTLNTNIKADDVPSDFLSLTSRLVGLILSKPGSYVA I53-47A: SEQ ID NO: 25VHINTDQQLSFGGSTNPAAFGTLMSIGGIEPDKNRDHSAVL 22, 25, 29, 72, 79, 86, 87FDHLNAMLGIPKNRMYIHFVNLNGDDVGWNGTTF I53-47A.1Ne(M)PIFTLNTNIKADDVPSDFLSLTSRLVGLILSPEGSYVA I53-47A: SEQ ID NO: 26VHINTDQQLSFGGSTNPAAFGTLMSIGGIEPDKNEDHSAVL 22, 25, 29, 72, 79, 86, 87FDHLNAMLGIPKNRMYIHFVDLDGDDVGWNGTTF I53-47B.1(M)NQHSHKDHETVRIAVVRARWHADIVDACVEAFEIAMAA I53-47B: SEQ ID NO: 27IGGDRFAVDVFDVPGAYEIPLHARTLAETGRYGAVLGTAFV 28, 31, 35, 36, 39, 131, 132,VNGGIYRHEFVASAVIDGMMNVQLDTGVPVLSAVLTPHRYR 135, 139, 146DSDEHHRFFAAHFAVKGVEAARACIEILNAREKIAA I53-47B.1Ne(M)NQHSHKDHETVRIAVVRARWHADIVDACVEAFEIAMAA I53-47B: gT2IGGDRFAVDVFDVPGAYEIPLHARTLAEDGRYFAVLGTAFV 28, 31, 35, 36, 39, 131, 132,SEQ ID NO: 28 VDGGIYDHEFVASAVIDGMMNVQLDTGVPVLSAVLTPHEYE 135, 139, 146DSDEDHEFFAAHFAVKGVEAARACIEILNAREKIAA I53-50A.1(M)KMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLI I53-50A: SEQ ID NO: 29IETFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAV 25, 29, 33, 54, 57ESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHDILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGDALVKGDPDEVREKAKKFVEKIRGC TE I53-50A.1Ne(M)KMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLI I53-50A: gT2EITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAV 25, 29, 33, 54, 57SEQ ID NO: 30 ESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHDILKLFPGEVVGPEFVEAMKGPFPNVKFVPTGGVDLDDVDEWFDAGVLAVGVGDALVEGDPDEVREDAKEFVEEIRGC TE I53-50A.1Pos(M)KMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLI I53-50A: T1EITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAV 25, 29, 33, 54, 57SEQ ID NO: 31 ESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHDILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCKWFKAGVLAVGVGKALVKGKPDEVREKAKKFVKKIRGC TE I53-50B.1(M)NQHSHKDHETVRIAVVRARWHAEIVDACVSAFEAAMRD I53-50B: SEQ ID NO: 32IGGDRFAVDVFDVPGAYEIPLHARTLAETGRYGAVLGTAFV24, 28, 36, 124, 125, 127,1 278,VNGGIYRHEFVASAVIDGMMNVQLDTGVPVLSAVLTPHRYR 129, 131, 132, 133, 135, 139DSDAHTLLFLALFAVKGMEAARACVEILAAREKIAA I53-50B.1Ne(M)NQHSHKDHETVRIAVVRARWHAEIVDACVSAFEAAMRD I53-50B: gT2IGGDRFAVDVFDVPGAYEIPLHARTLAETGRYGAVLGTAFV24, 28, 36, 124, 125, 127, 128, SEQ ID NO: 33VDGGIYDHEFVASAVIDGMMNVQLDTGVPVLSAVLTPHEYE 129, 131, 132, 133, 135, 139DSDADTLLFLALFAVKGMEAARACVEILAAREKIAA I53-50B.4Pos(M)NQHSHKDHETVRIAVVRARWHAEIVDACVSAFEAAMRD I53-50B: T1IGGDRFAVDVFDVPGAYEIPLHARTLAETGRYGAVLGTAFV24, 28, 36, 124, 125, 127, 128, SEQ ID NO: 34VNGGIYRHEFVASAVINGMMNVQLNTGVPVLSAVLTPHNYD 129, 131, 132, 133, 135, 139KSKHATLLFLALFAVKGMEAARACVEILAAREKIAA

I53-40A genus (SEQ ID NO: 35)(M)TKKVGIVDTTFARVDMASAAILTLKMESPNIKIIRKTVPGIKDLPVACKKLLEEEGCDIVMALGMPGK(A/K)EKDKVCAHEASLGLMLAQLMTNKHIIEVEVHEDEAKDDAELKILAARRAIEHALNVYYLLFKPEYLTRMAGKGLRQGFEDAGPARE I53-40B genus (SEQ ID NO: 36) (M)(S/D)(T/D)INNQLK(A/R)LNVIPVIAIDNAEDIIPLGKVLAENGLPAAEITFRSSAAVKAIMLLRSAQPEMLIGAGTILNGVQALAAKEAGA(T/D)FVVSPGFNPNTVRACQIIGIDIVPGVNNPSTVE(A/Q)ALEMGLTTLKFFPAEASGGISMVKSLVGPYGDIRLMPTGGITP(S/D)NIDNYLAIPQVLACGGTWMVDKKLV(T/R)NGEWDEIARLTREIVEQVNP I53-47A genus (SEQ ID NO: 37)(M)PIFTLNTNIKA(T/D)DVPSDFLSLTSRLVGLILS(K/E)PGSYVAVHINTDQQLSFGGSTNPAAFGTLMSIGGIEP(S/D)KN(R/E)DHSAVLFDHLNAMLGIPKNRMYIHFV(N/D)L(N/D)GDDVGWNGTTF I53-47B genus (SEQ ID NO: 38)(M)NQHSHED(Y/H)ETVRIAVVRARWHADIVDACVEAFEIAMAAIGGDRFAVDVFDVPGAYEIPLHARTLAETGRYGAVLGTAFVV(N/D)GGIY(R/D)HEFVASAVIDGMMNVQL(S/D)TGVPVLSAVLTPH(R/E)Y(R/E)DS(A/D)E(H/D)H(R/E)FFAAHFAVKGVEAARACIEIL(A/N)ARE KIAAI53-50A genus (SEQ ID NO: 39)(M)KMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGH(T/D)ILKLFPGEVVGP(Q/E)FV(K/E)AMKGPFPNVKFVPTGGV(N/D)LD(N/D)VC(E/K)WF(K/D)AGVLAVGVG(S/K/D)ALV(K/E)G(T/D/K)PDEVRE(K/D)AK(A/E/K)FV(E/K)(K/E)IRGCTE I53-50B genus (SEQ ID NO: 40)(M)NQHSHKD(Y/H)ETVRIAVVRARWHAEIVDACVSAFEAAM(A/R)DIGGDRFAVDVFDVPGAYEIPLHARTLAETGRYGAVLGTAFVV(N/D)GGIY(R/D)HEFVASAVI(D/N)GMMNVQL(S/D/N)TGVPVLSAVLTPH(R/E/N)Y(R/D/E)(D/K)S(D/K)A(H/D)TLLFLALFAVKGMEAARACVEILAAREKIAA T32-28A (SEQ ID NO: 41)(M)GEVPIGDPKELNGMEIAAVYLQPIEMEPRGIDLAASLADIHLEADIHALKNNPNGFPEGFWMPYLTIAYALANADTGAIKTGTLMPMVADDGPHYGANIAMEKDKKGGFGVGTYALTFLISNPEKQGFGRHVDEETGVGKWFEPFVVTYFFKYTGTPK T32-28B (SEQ ID NO: 42)(M)SQAIGILELTSIAKGMELGDAMLKSANVDLLVSKTISPGKFLLMLGGDIGAIQQAIETGTSQAGEMLVDSLVLANIHPSVLPAISGLNSVDKRQAVGIVETWSVAACISAADLAVKGSNVTLVRVHMAFGIGGKCYMVVAGDVLDVAAAVATASLAAGARGLLVYASIIPRPHEAMWRQMVEG T33-09A(SEQ ID NO: 43)(M)EEVVLITVPSALVAVKIAHALVEERLAACVNIVPGLTSIYRWQGSVVSDHELLLLVKTTTHAFPKLKERVKALHPYTVPEIVALPIAEGNREYLDWLRENTG T33-09B (SEQ ID NO: 44)(M)VRGIRGAITVEEDTPAAILAATIELLLKMLEANGIQSYEELAAVIFTVTEDLTSAFPAEAARLIGMHRVPLLSAREVPVPGSLPRVIRVLALWNTDTPQDRVRHVYLNEAVRLRPDLESAQ T33-15A(SEQ ID NO: 45)(M)SKAKIGIVTVSDRASAGITADISGKAIILALNLYLTSEWEPIYQVIPDEQDVIETTLIKMADEQDCCLIVTTGGTGPAKRDVTPEATEAVCDRMMPGFGELMRAESLKEVPTAILSRQTAGLRGDSLIVNLPGDPASISDCLLAVFPAIPYCIDLMEGPYLECNEAMIKPFRPKAK T33-15B(SEQ ID NO: 46)(M)VRGIRGAITVNSDTPTSIIIATILLLEKMLEANGIQSYEELAAVIFTVTEDLTSAFPAEAARQIGMHRVPLLSAREVPVPGSLPRVIRVLALWNTDTPQDRVRHVYLSEAVRLRPDLESAQ T33-21A(SEQ ID NO: 47)(M)RITTKVGDKGSTRLFGGEEVWKDSPIIEANGTLDELTSFIGEAKHYVDEEMKGILEEIQNDIYKIMGEIGSKGKIEGISEERIAWLLKLILRYMEMVNLKSFVLPGGTLESAKLDVCRTIARRALRKVLTVTREFGIGAEAAAYLLALSDLLFLLARVIElEKNKLKEVRS T33-21B (SEQ ID NO: 48)(M)PHLVIEATANLRLETSPGELLEQANKALFASGQFGEADIKSRFVTLEAYRQGTAAVERAYLHACLSILDGRDIATRTLLGASLCAV1AEAVAGGGEEGVQVSVEVREMERLSYAKRVVARQR T33-28A(SEQ ID NO: 49)(M)ESVNTSFLSPSLVTIRDFDNGQFAVLRIGRTGFPADKGDIDLCLDKMIGVRAAQIFLGDDTEDGFKGPHIRIRCVDIDDKHTYNAMVYVDLIVGTGASEVERETAEEEAKLALRVALQVDIADEHSCVTQFEMKLREELLSSDSFHPDKDEYYKDFL T33-28B (SEQ ID NO: 50)(M)PVIQTFVSTPLDHHKRLLLAIIYRIVTRVVLGKPEDLVMMTFHDSTPMHFFGSTDPVACVRVEALGGYGPSEPEKVTSIVTAAITAVCGIVADRIFVLYFSPLHCGWNGTNF T33-31A(SEQ ID NO: 51)(M)EEVVLITVPSALVAVKIAHALVEERLAACVNIVPGLTSIYREEGSVVSDHELLLLVKTTTDAFPKLKERVKELHPYEVPEIVALPIAEGNREYLDWLRENTG

Table 1 provides the amino acid sequence of the first and secondpolypeptides; the right hand column in Table 1 identifies the residuenumbers in each exemplary polypeptide that were identified as present atthe interface of resulting assembled nanostructures (i.e.: “identifiedinterface residues”). As can be seen, the number of interface residuesfor the exemplary polypeptides of SEQ ID NO:1-34 range from 4-13. Invarious embodiments, the first and second polypeptides comprise an aminoacid sequence that is at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%,95%, 96%, 97%, 98%, or 99% identical over its length, and identical atleast at 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13 identifiedinterface positions (depending on the number of interface residues for agiven polypeptide), to the amino acid sequence of a polypeptide selectedfrom the group consisting of SEQ ID NOS: 1-34. In other embodiments, thefirst and second polypeptides comprise an amino acid sequence that is atleast 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%identical over its length, and identical at least at 20%, 25%, 33%, 40%,50%, 60%, 70%, 75%, 80%, 90%, or 100% of the identified interfacepositions, to the amino acid sequence of a polypeptide selected from thegroup consisting of SEQ ID NOS:1-51.

As is the case with proteins in general, the polypeptides are expectedto tolerate some variation in the designed sequences without disruptingsubsequent assembly into nanostructures: particularly when suchvariation comprises conservative amino acid substitutions. As used here,“conservative amino acid substitution” means that: hydrophobic aminoacids (Ala, Cys, Gly, Pro, Met, See, Sme, Val, Ile, Leu) can only besubstituted with other hydrophobic amino acids; hydrophobic amino acidswith bulky side chains (Phe, Tyr, Trp) can only be substituted withother hydrophobic amino acids with bulky side chains; amino acids withpositively charged side chains (Arg, His, Lys) can only be substitutedwith other amino acids with positively charged side chains; amino acidswith negatively charged side chains (Asp, Glu) can only be substitutedwith other amino acids with negatively charged side chains; and aminoacids with polar uncharged side chains (Ser, Thr, Asn, Gln) can only besubstituted with other amino acids with polar uncharged side chains.

Table 2 lists surface amino acid residue numbers for each exemplarypolypeptide of the invention denoted by SEQ ID NOS: 1-34. Thus, invarious embodiments, 1 or more (at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 2728,29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46,47, 48, 49, 50, or more) of these surface residues may be modified inthe polypeptides of the invention. Residues in parentheses are optional.

TABLE 2 Name Amino Acid Sequence Surface residues not near interfaceI53-34A (M)EGMDPLAVLAESRLLPLLTVRGGEDLAGLATVLELMGV I53-34A: SEQ ID NO: 1GALEITLRTEKGLEALKALRKSGLLLGAGTVRSPKEAEAAL6, 8, 9, 12, 14, 22, 25, 48, 49, 50,EAGAAFLVSPGLLEEVAALAQARGVPYLPGVLTPTEVERAL52, 53, 56, 73, 74, 81, 94, 95, 101,ALGLSALKFFPAEPFQGVRVLRAYAEVFPEVRFLPTGGIKE102, 103, 104, 119, 122, 137, 140,EHLPHYAALPNLLAVGGSWLLQGDLAAVMKKVKAAKALLSP143, 147, 150, 151, 153, 161, 162, QAPG163, 164, 166, 167, 170, 172, 184, 193, 198, 199, 200, 202 I53-34B(M)TKKVGIVDTTFARVDMAEAAIRTLKALSPNIKIIRKTV I53-34B: SEQ ID NO: 2PGIKDLPVACKKLLEEEGCDIVMALGMPGKAEKDKVCAHEA3, 12, 31, 33, 35, 36, 51, 54, 55,SLGLMLAQLMTNKHIIEVFVHEDEAKDDDELDILALVRAIE56, 59, 69, 70, 71, 74, 93, 103, HAANVYYLLFKPEYLTRMAGEGLRQGREDAGPARE106, 107, 108, 131, 132, 133, 134, 138, 142, 153 I53-40A(M)TKKVGIVDTTFARVDMASAAILTLKMESPNIKIIRKTV I53-40A: SEQ ID NO: 3PGIKDLPVACKKLLEEEGCDIVMALGMPGKAEKDKVCAHEA3, 4, 31, 33, 35, 36, 37, 51, 54,SLGLMLAQLMTNKHIIEVFVHEDEAKDDAELKILAARRAIE55, 56, 57, 59, 69, 70, 71, 74, 93, HALNVYYLLFKPEYLTRMAGKGLRQGFEDAGPARE103, 106, 118, 127, 128, 131, 132, 133, 134, 135, 138, 139, 142, 150,153 I53-40B (M)STINNQLKALKVIPVIAIDNAEDIIPLGKVLAENGLPA I53-40B:SEQ ID NO: 4 AEITFRSSAAVKAIMLLRSAQPEMLIGAGTILNGVQALAAK2, 3, 7, 9, 10, 12, 20, 21, 23, 26,EAGATFVVSPGFNPNTVRACQIIGIDIVPGVNNPSTVEAAL77, 30, 34, 38, 45, 60, 62, 75, 85,EMGLTTLKFFPAEASGGISMVKSLVGPYGDIRLMPTGGITP94, 95, 122, 124, 126, 134, 139,SNIDNYLAIPQVLACGGTWMVDKKLVTNGEWDEIARLTREI143, 151, 153, 161, 163, 166, 167, VEQVNP170, 172, 180, 184, 185, 186, 189, 190, 192, 193, 194, 195, 198, 201,202, 205, 208, 209 I53-47A (M)PIFTLNTNIKATDVPSDFLSLTSRLVGLILSKPGSYVAI53-47A: SEQ ID NO: 5 VHINTDQQLSFGGSTNPAAFGTLMSIGGIEPSKNRDHSAVL11, 13, 14, 17, 34, 36, 37, 45, 47, FDHLNAMLGIPKNRMYIHFVNLNGDDVGWNGTTF54, 55, 56, 65, 69, 70, 71, 74, 91, 92, 93, 101, 103, 105, 109, 110,112, 114 I53-47B (M)NQHSHKDYETVRIAVVRARWHADIVDACVEAFEIAMAA I53-47B:SEQ ID NO: 6 IGGDRFAVDVFDVPGAYEIPLHARTLAETGRYGAVLGTAFV6, 7, 8, 9, 10, 11, 13, 18, 20, 21,VNGGIYRHEFVASAVIDGMMNVQLSTGVPVLSAVLTPHRYR24, 43, 44, 51, 63, 67, 70, 85, 87, DSAEHHRFFAAHFAVKGVEAARACIEILAAREKIAA101, 105, 122, 123, 124, 125, 126, 147, 152, 153, 154 I53-50A(M)KMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLI I53-50A: SEQ ID NO: 7EITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAV4, 5, 6, 8, 9, 11, 17, 19, 23, 37,ESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAM46, 47, 59, 74, 77, 78, 81, 94, 95,KLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLD98, 101, 102, 103, 106, 119, 122,NVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGC126, 139, 142, 145, 149, 150, 152, TE 160, 161, 162, 163, 166, 169, 179,183, 185, 188, 191, 192, 194, 198, 199 I53-50B(M)NQHSHKDYETVRIAVVRARWHAEIVDACVSAFEAAMAD I53-50B: SEQ ID NO: 8IGGDRFAVDVFDVPGAYEIPLHARTLAETGRYGAVLGTAFV6, 7, 8, 9, 10, 11, 13, 18, 20, 21,VNGGIYRHEFVASAVIDGMMNVQLSTGVPVLSAVLTPHRYR34, 38, 39, 40, 43, 44, 48, 51, 63, DSDAHTLLFLALFAVKGMEAARACVEILAAREKIAA67, 70, 87, 101, 105, 118, 143, 147, 152, 153, 154 I53-51A(M)FTKSGDDGNTNVINKRVGKDSPLVNFLGDLDELNSFIG I53-51A: SEQ ID NO: 9FAISKIPWEDMKKDLERVQVELFEIGEDLSTQSSKKKIDES19, 20, 24, 28, 46, 47, 51, 70, 71,YVLWLLAATAIYRIESGPVKLFVIPGGSEEASVLHVTRSVA73, 74, 75, 76, 102, 122, 130, 133,RRVERNAVKYTKELPEINRMIIVYLNRLSSLLFAMALVANK134, 135, 136, 137, 140, 162, 163, RRNQSEKIYEIGKSW164, 165, 169, 175, 177 I53-51B(M)NQHSHKDYETVRIAVVRARWHADIVDQCVRAFEEAMAD I53-51B: SEQ ID NO: 10AGGDRFAVDVFDVPGAYEIPLHARTLAETGRYGAVLGTAFV6, 7, 8, 9, 10, 11, 13, 18, 21, 27,VNGGIYRHEFVASAVIDGMMNVQLSTGVPVLSAVLTPHRYR34, 38, 43, 48, 63, 67, 70, 85, 87, SSREHHEFFREHFMVKGVEAAAACITILAAREKIAA101, 118, 125, 126, 129, 152, 153, 154 I52-03A(M)GHTKGPTPQQHDGSALRIGIVHARWNKTIIMPLLIGTI I52-03A: SEQ ID NO: 11AKLLECGVKASNIVVQSVPGSWELPIAVQRLYSASQLQTPS6, 9, 10, 11, 13, 15, 16, 26, 48,SGPSLSAGDLLGSSTTDLTALPTTTASSTGPFDALIAIGVL69, 75, 76, 78, 79, 111, 125, 127,IKGETMHFEYIADSVSHGLMRVQLDTGVPVIFGVLTVLTDD142, 146, 159, 160, 161, 162, 171,QAKARAGVIEGSHNHGEDWGLAAVEMGVRRRDWAAGKTE175, 193, 194, 196, 197, 199, 200 I52-03B(M)YEVDHADVYDLFYLGRGKDYAAEASDIADLVRSRTPEA I52-03B: SEQ ID NO: 12SSLLDVACGTGTHLEHFTKEFGDTAGLELSEDMLTHARKRL2, 3, 5, 6, 8, 15, 17, 20, 22, 23,PDATLHQGDMRDFQLGRKFSAVVSMFSSVGYLKTVAELGAA26, 27, 30, 33, 34, 35, 37, 38, 40,VASFAEHLEPGGVVVVEPWWFPETFADGWVSADVVRRDGRT54, 55, 57, 58, 59, 61, 62, 68, 70,VARVSHSVREGNATRMEVHFTVADPGKGVRHFSDVHLITLF71, 74, 77, 78, 79, 81, 82, 84, 86, HQREYEAAFMAAGLRVEYLEGGPSGRGLFVGVPA87, 91, 96, 97, 98, 111, 127, 130, 131, 132, 141, 144, 145, 148, 150,154, 157, 158, 159, 160, 161, 171, 172, 173, 174, 177, 187, 189, 192,198, 199, 222, 223, 224, 236 I52-32A(M)GMKEKFVLIITHGDFGKGLLSGAEVIIGKQENVHTVGL I52-32A: SEQ ID NO: 13NLGDNIEKVAKEVMRIIIAKLAEDKEIIIVVDLFGGSPFNI3, 5, 15, 18, 30, 32, 35, 40, 41,ALEMMKTFDVKVITGINMPMLVELLTSINVYDTTELLENIS42, 44, 45, 65, 73, 79, 91, 103, KIGKDGIKVIEKSSLKM106, 109, 110, 111, 112, 114, 115, 118, 122, 123, 125, 126, 129, 131I52-32B (M)KYDGSKLRIGILHARWNLEIIAALVAGAIKRLQEFGVK I52-32B: SEQ ID NO: 14AENIIIETVPGSFELPYGSKLFVEKQKRLGKPLDAIIPIGV4, 6, 7, 9, 17, 32, 35, 42, 59, 63,LIKGSTMHFEYICDSTTHQLMKLNFELGIPVIFGVLTCLTD64, 66, 67, 68, 69, 70, 71, 73, 83, EQAEARAGLIEGKMHNHGEDWGAAAVEMATKFN85, 90, 106, 119, 120, 121, 122, 125, 131, 133, 134, 135, 136, 154I52-33A (M)AVKGLGEVDQKYDGSKLRIGILHARWNRKIILALVAGA I52-33A: SEQ ID NO: 15VLRLLEFGVKAENIIIETVPGSFELPYGSKLFVEKQKRLGK12, 14, 16, 17, 19, 26, 27, 46, 69,PLDAIIPIGVLIKGSTMHFEYICDSTTHQLMKLNFELGIPV73, 74, 76, 77, 78, 80, 81, 83, 93,IFGVLTCLTDEQAEARAGLIEGKMHNHGEDWGAAAVEMATK95, 100, 116, 129, 130, 131, 132, FN 145, 164 I52-33B(M)GANWYLDNESSRLSFTSTKNADIAEVHRFLVLHGKVDP I52-33B: SEQ ID NO: 16KGLAEVEVETESISTGIPLRDMLLRVLVFQVSKFPVAQINA4, 6, 10, 20, 21, 23, 24, 31, 32,QLDMRPINNLAPGAQLELRLPLTVSLRGKSHSYNAELLATR34, 36, 39, 40, 42, 44, 46, 48, 56,LDERRFQVVTLEPLVIHAQDFDMVRAFNALRLVAGLSAVSL73, 77, 79, 81, 83, 85, 88, 89, 91, SVPVGAVLIFTAR92, 96, 97, 99, 101, 103, 109, 110, 111, 112, 114, 124, 125, 138, 140,143, 158, 175 I32-06A (M)TDYIRDGSAIKALSFAIILAEADLRHIPQDLQRLAVRV I32-06A:SEQ ID NO: 17 IHACGMVDVANDLAFSEGAGKAGRNALLAGAPILCDARMVA24, 26, 27, 41, 47, 50, 51, 56, 60EGITRSRLPADNRVIYTLSDPSVPELAKKIGNTRSAAALDL, 63, 64, 67, 68, 77, 84, 85, 86,WLPHIEGSIVAIGNAPTALFRLFELLDAGAPKPALIIGMPV91, 93, 98, 99, 100, 101, 102, 105,GFVGAAESKDELAANSRGVPYVIVRGRRGGSAMTAAAVNAL108, 109, 114, 123, 124, 125, 127, ASERE135, 142, 145, 148, 149, 152, 153, 169, 172, 173, 176, 177, 180, 187,189 I32-06B (M)ITVFGLKSKLAPRREKLAEVIYSSLHLGLDIPKGKHAI I32-06B:SEQ ID NO: 18 RFLCLEKEDFYYPFDRSDDYTVIEINLMAGRSEETKMLLIF8, 9, 10, 13, 14, 15, 16, 17, 20,LLFIALERKLGIRAHDVEITIKEQPAHCWGFRGRTGDSARD34, 36, 45, 46, 47, 50, 51, 53, 54, LDYDIYV57, 67, 70, 91, 93, 95, 105, 112 I32-19A(M)GSDLQKLQRFSTCDISDGLLNVYNIPTGGYFPNLTAIS I32-19A: SEQ ID NO: 19PPQNSSIVGTAYTVLFAPIDDPRPAVNYIDSVPPNSILVLA3, 4, 6, 7, 9, 10, 25, 27, 36, 40,LEPHLQSQFHPFIKITQAMYGGLMSTRAQYLKSNGTVVFGR42, 43, 44, 49, 58, 59, 61, 62, 63,IRDVDEHRTLNHPVFAYGVGSCAPKAVVKAVGTNVQLKILT70, 72, 73, 74, 82, 84, 88, 89, 109,SDGVTQTICPGDYIAGDNNGIVRIPVQETDISKLVTYIEKS110, 112, 126, 127, 129, 130, 132, IEVDRLVSEAIKNGLPAKAAQTARRMVLKDYI146, 155, 156, 157, 159, 166, 169, 172, 189, 190, 192, 194, 195, 198,201, 204, 215, 232 I32-19B (M)SGMRVYLGADHAGYELKQAIIAFLKMTGHEPIDCGALRI32-19B: SEQ ID NO: 20 YDADDDYPAFCIAAATRTVADPGSLGIVLGGSGNGEQIAAN4, 5, 31, 33, 38, 41, 42, 43, 55,KVPGARCALAWSVQTAALAREHNNAQLIGIGGRMHTLEEAL56, 59, 61, 62, 83, 93, 94, 101,RIVKAFVTTPWSKAQRHQRRIDILAEYERTHEAPPVPGAPA104, 113, 119, 129, 131, 134, 136, 137, 139, 140, 143, 144, 146, 147,150, 152, 153, 156, 158, 159 I32-28A(M)GDDARIAAIGDVDELNSQIGVLLAEPLPDDVRAALSAI I32-28A: SEQ ID NO: 21QHDLFDLGGELCIPGHAAITEDHLLRLALWLVHYNGQLPPL4, 6, 7, 10, 14, 27, 30, 31, 33, 34,EEFILPGGARGAALAHVCRTVCRRAERSIKALGASEPLNIA41, 44, 45, 51, 52, 53, 54, 55, 56, PAAYVNLLSDLLFVLARVLNRAAGGADVLWDRTRAH59, 76, 78, 79, 80, 81, 82, 83, 90, 103, 111, 115, 116, 131, 134, 142,145, 147, 150 I32-28B (M)ILSAEQSFTLRHPHGQAAALAFVREPAAALAGVQRLRG I32-28B:SEQ ID NO: 22 LDSDGEQVWGELLVRVPLLGEVDLPFRSEIVRTPQGAELRP3, 4, 6, 8, 12, 15, 17, 18, 22, 26,LTLTGERAWVAVSGQATAAEGGEMAFAFQFQAHLATPEAEG28, 32, 38, 39, 41, 43, 45, 46, 48, EGGAAFEVMVQAAAGVTLLLVAMALPQGLAAGLPPA50, 60, 66, 68, 71, 73, 74, 79, 81, 82, 83, 84, 86, 87, 95, 100, 103,105, 109, 111, 113, 151, 152, 155, 156, 157 I53-40A.1(M)TKKVGIVDTTFARVDMASAAILTLKMESPNIKIIRKTV I53-40A: SEQ ID NO: 23PGIKDLPVACKKLLEEEGCDIVMALGMPGKKEKDKVCAHEA3, 4, 31, 33, 35, 36, 37, 51, 54,SLGLMLAQLMTNKHIIEVFVHEDEAKDDAELKILAARRAIE55, 56, 57, 59, 69, 70, 71, 74, 93, HALNVYYLLFKPEYLTRMAGEGLRQGFEDAGPARE103, 106, 118, 127, 128, 131, 132, 133, 134, 135, 138, 139, 142, 150,153 I53-40B.1 (M)DDINNQLKRLKVIPVIAIDNAEDIIPLGKVLAENGLPA I53-40B:SEQ ID NO: 24 ASITFRSSAAVKAIMLLRSAQPEMLIGAGTILNGVQALAAK2, 3, 7, 9, 10, 12, 20, 21, 23, 26,EAGADFVVSPGFNPNTVRACQIIGIDIVPGVNNPSTVEQAL27, 30, 34, 38, 45, 60, 62, 75, 85,EMGLTTLKFFPAEASGGISMVKSLVGPYGDIRLMPTGGITP94, 95, 122, 124, 126, 134, 139,DNIDNYLAIPQVLACGGTWMVDKKLVRNGEWDEIARLTREI143, 151, 153, 161, 163, 166, 167, VEQVNP170, 172, 180, 184, 185, 186, 189, 190, 192, 193, 194, 195, 198, 201,202, 205, 208, 209 I53-47A, 1 (M)PIFTLNTNIKADDVPSDFLSLTSRLVGLILSKPGSYVAI53-47A: SEQ ID NO: 25 VHINTDQQLSFGGSTNPAAFGTLMSIGGIEPDKNRDHSAVL11, 13, 14, 17, 34, 36, 37, 45, 47, FDHLNAMLGIPKNRMYIHFVNLNGDDVGWNGTTF54, 55, 56, 65, 69, 70, 71, 74, 91, 92, 93, 101, 103, 105, 109, 110,112, 114 I53-47A.1Ne (M)PIFTLNTNIKADDVPSDFLSLTSRLVGLILSEPGSYVA I53-47A:SEQ ID NO: 26 VHINTDQQLSFGGSTNPAAFGTLMSIGGIEPDKNEDHSAVL11, 13, 14, 17, 34, 36, 37, 45, 47, gT2FDHLNAMLGIPKNRMYIHFVDLDGDDVGWNGTTF 54, 55, 56, 65, 69, 70, 71, 74, 91,92, 93, 101, 103, 105, 109, 110, 112, 114 I53-47B.1(M)NQHSHKDHETVRIAVVRARWHADIVDACVEAFEIAMAA I53-47B: SEQ ID NO: 27IGGDRFAVDVFDVPGAYEIPLHARTLAETGRYGAVLGTAFV6, 7, 8, 9, 10, 11, 13, 18, 20, 21,VNGGIYRHEFVASAVIDGMMNVQLDTGVPVLSAVLTPHRYR24, 43, 44, 51, 63, 67, 70, 85, 87, DSDEHHRFFAAHFAVKGVEAARACIEILNAREKIAA101, 105, 122, 123, 124, 125, 126, 147, 152, 153, 154 I53-47B.1Ne(M)NQHSHKDHETVRIAVVRARWHADIVDACVEAFEIAMAA I53-47B: SEQ ID NO: 28IGGDRFAVDVFDVPGAYEIPLHARTLAETGRYGAVLGTAFV6, 7, 8, 9, 10, 11, 13, 18, 20, 21, gT2VDGGIYDHEFVASAVIDGMMNVQLDTGVPVLSAVLTPHEYE24, 43, 44, 51, 63, 67, 70, 85, 87, DSDEDHEFFAAHFAVKGVEAARACIEILNAREKIAA101, 105, 122, 123, 124, 125, 126, 147, 152, 153, 154 I53-50A.1(M)KMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLI I53-50A: SEQ ID NO: 29EITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAV4, 5, 6, 8, 9, 11, 17, 19, 23, 37,ESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAM46, 47, 59, 74, 77, 78, 81, 94, 95,KLGHDILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLD98, 101, 102, 103, 106, 119, 122,NVCEWFKAGVLAVGVGDALVEGDPDEVREKAKKFVEKIRGC126, 139, 142, 145, 149, 150, 152, TE 160, 161, 162, 163, 166, 169, 179,183, 185, 188, 191, 192, 194, 198, 199 I53-50A.1Ne(M)KMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLI I53-50A: SEQ ID NO: 30EITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAV4, 5, 6, 8, 9, 11, 17, 19, 23, 37, gT2ESGAEFIVSPHLDEEISQFCKEKGVEYMPGVMTPTELVKAM46, 47, 59, 74, 77, 78, 81, 94, 95,KLGHDILKLFPGEVVGPEFVEAMKGPFPNVKFVPTGGVDLD98, 101, 102, 103, 106, 119, 122,DVCEWFDAGVLAVGVGDALVEGDPDEVREDAKEFVEEIRGC126, 139, 142, 145, 149, 150, 152, TE 160, 161, 162, 163, 166, 169, 179,183, 185, 188, 191, 192, 194, 198, 199 I53-50A.1Pos(M)KMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLI I53-50A: SEQ ID NO: 31EITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAV4, 5, 6, 8, 9, 11, 17, 19, 23, 37, T1ESGAEFIVSPHLDEEISQFCKEKGVEYMPGVMTPTELVKAM46, 47, 59, 74, 77, 78, 81, 94, 95,KLGHDILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLD98, 101, 102, 103, 106, 119, 122,NVCKWFKAGVLAVGVGKALVKGKPDEVREKAKKFVKKIRGC126, 139, 142, 145, 149, 150, 152, TE 160, 161, 162, 163, 166, 169, 179,183, 185, 188, 191, 192, 194, 198, 199 I53-50B.1(M)NQHSHKDHETVRIAVVRARWHAEIVDACVSAFEAAMRD I53-50B: SEQ ID NO: 32IGGDRFAVDVFDVPGAYEIPLHARTLAETGRYGAVLGTAFV6, 7, 8, 9, 10, 11, 13, 18, 20, 21,VNGGIYRHEFVASAVIDGMMNVQLDTGVPVLSAVLTPHRYR34, 38, 39, 40, 43, 44, 48, 51, 63, DSDAHTLLFLALFAVKGMEAARACVEILAAREKIAA67, 70, 87, 101, 105, 118, 143, 147, 152, 153, 154 I53-50B.1Ne(M)NQHSHKDHETVRIAVVRARWHAEIVDACVSAFEAAMRD I53-50B: SEQ ID NO: 33IGGDRFAVDVFDVPGAYEIPLHARTLAETGRYGAVLGTAFV6, 7, 8, 9, 10, 11, 13, 18, 20, 21, gT2VDGGIYDHEFVASAVIDGMMNVQLDTGVPVLSAVLTPHEYE34, 38, 39, 40, 43, 44, 48, 51, 63, DSDADTLLFLALFAVKGMEAARACVEILAAREKIAA67, 70, 87, 101, 105, 118, 143, 147, 152, 153, 154 I53-50B.4Pos(M)NQHSHKDHETVRIAVVRARWHAEIVDACVSAFEAAMRD I53-50B: SEQ ID NO: 34IGGDRFAVDVFDVPGAYEIPLHARTLAETGRYGAVLGTAFV6, 7, 8, 9, 10, 11, 13, 18, 20, 21, T1VNGGIYRHEFVASAVINGMMNVQLNTGVPVLSAVLTPHNYD34, 38, 39, 40, 43, 44, 48, 51.63, KSKAHTLLFLALFAVKGMEAARACVEILAAREKIAA67, 70, 87, 101, 105, 118, 143, 147, 152, 153, 154

In various embodiments of the nanostructure of the invention, the firstpolypeptides and the second polypeptides comprise polypeptides with theamino acid sequence selected from the following pairs, or modifiedversions thereof (i.e.: permissible modifications as disclosed for thepolypeptides of the invention: isolated polypeptides comprising an aminoacid sequence that is at least 75% 80%, 85%, 90%, 91%, 92%, 93%, 94%,95%, 96%, 97%, 98%, 99%, or 100% identical over its length, and/oridentical at least at one identified interface position, to the aminoacid sequence indicated by the SEQ ID NO.):

SEQ ID NO:1 and SEQ ID NO:2 (153-34A and 153-34B);

SEQ ID NO:3 and SEQ ID NO:4 (153-40A and 153-40B);

SEQ ID NO:3 and SEQ ID NO:24 (153-40A and I53-40B.1);

SEQ ID NO:23 and SEQ ID NO:4 (I53-40A.1 and I53-40B);

SEQ ID NO:35 and SEQ ID NO:36 (I53-40A genus and 153-40B genus);

SEQ ID NO:5 and SEQ ID NO:6 (153-47A and 153-47B);

SEQ ID NO:5 and SEQ ID NO:27 (153-47A and 153-47B.1);

SEQ ID NO:5 and SEQ ID NO:28 (153-47A and 153-47B.1NegT2);

SEQ ID NO:25 and SEQ ID NO:6 (153-47A.1 and 153-47B);

SEQ ID NO:25 and SEQ ID NO:27 (I53-47A.1 and I53-47B.1);

SEQ ID NO:25 and SEQ ID NO:28 (I53-47A.1 and I53-47B.1NegT2);

SEQ ID NO:26 and SEQ ID NO:6 (153-47A.1NegT2 and 153-47B);

SEQ ID NO:26 and SEQ ID NO:27 (I53-47A.1NegT2 and 153-47B.1);

SEQ ID NO:26 and SEQ ID NO:28 (I53-47A.1NegT2 and I53-47B.1NegT2);

SEQ ID NO:37 and SEQ ID NO:38 (I53-47A genus and 153-47B genus);

SEQ ID NO:7 and SEQ ID NO:8 (I53-50A and I53-50B);

SEQ ID NO:7 and SEQ ID NO:32 (153-50A and 153-50B.1);

SEQ ID NO:7 and SEQ ID NO:33 (153-50A and 153-50B.1NegT2);

SEQ ID NO:7 and SEQ ID NO:34 (153-50A and 153-50B.4PosT1);

SEQ ID NO:29 and SEQ ID NO:8 (I53-50A.1 and I53-50B);

SEQ ID NO:29 and SEQ ID NO:32 (153-50A.1 and I53-50B.1);

SEQ ID NO:29 and SEQ ID NO:33 (153-50A.1 and I53-50B.1NegT2);

SEQ ID NO:29 and SEQ ID NO:34 (153-50A.1 and I53-50B.4PosT1);

SEQ ID NO:30 and SEQ ID NO:8 (I53-50A.1NegT2 and I53-50B);

SEQ ID NO:30 and SEQ ID NO:32 (I53-50A.1NegT2 and I53-50B.1);

SEQ ID NO:30 and SEQ ID NO:33 (153-50A.1NegT2 and I53-50B.1NegT2);

SEQ ID NO:30 and SEQ ID NO:34 (153-50A.1NegT2 and I53-50B.4PosT1);

SEQ ID NO:31 and SEQ ID NO:8 (I53-50A.1PosT1 and I53-50B);

SEQ ID NO:31 and SEQ ID NO:32 (153-50A.1PosT1 and I53-50B.1);

SEQ ID NO:31 and SEQ ID NO:33 (153-50A.1PosT1 and I53-50B.1NegT2);

SEQ ID NO:31 and SEQ ID NO:34 (153-50A.1PosT1 and I53-50B.4PosT1);

SEQ ID NO:39 and SEQ ID NO:40 (153-50A genus and I53-50B genus);

SEQ ID NO:9 and SEQ ID NO:10 (I53-51A and I53-51B);

SEQ ID NO:11 and SEQ ID NO:12 (152-03A and I52-03B);

SEQ ID NO:13 and SEQ ID NO:14 (152-32A and I52-32B);

SEQ ID NO:15 and SEQ ID NO:16 (I52-33A and I52-33B)

SEQ ID NO:17 and SEQ ID NO:18 (132-06A and 132-06B);

SEQ ID NO:19 and SEQ ID NO:20 (132-19A and 132-19B);

SEQ ID NO:21 and SEQ ID NO:22 (132-28A and I32-28B);

SEQ ID NO:23 and SEQ ID NO:24 (153-40A.1 and I53-40B.1);

SEQ ID NO:41 and SEQ ID NO:42 (T32-28A and T32-28B);

SEQ ID NO:43 and SEQ ID NO:44 (T33-09A and T33-09B);

SEQ ID NO:45 and SEQ ID NO:46 (T33-15A and T33-15B);

SEQ ID NO:47 and SEQ ID NO:48 (T33-21A and T33-21B);

SEQ ID NO:49 and SEQ ID NO:50 (T33-28A and T32-28B); and

SEQ ID NO:51 and SEQ ID NO:44 (T33-31A and T33-09B (also referred to asT33-31B))

In one embodiment, the one or more paramyxovirus and/or pneumovirus Fproteins, or antigenic fragments thereof, are expressed as a fusionprotein with the first and/or second polypeptides. In these embodiments,it is preferred that the one or more paramyxovirus and/or pneumovirus Fproteins, or antigenic fragments thereof are present at the N terminusof the fusion protein, whenever this configuration can facilitatepresentation of the one or more paramyxovirus and/or pneumovirus Fproteins, or antigenic fragments thereof on an exterior of thenanostructure. This preference for the presence of the paramyxovirusand/or pneumovirus F protein at the N terminus of the fusion proteinderives from the location of the C terminus of the paramyxovirus and/orpneumovirus F proteins at one extreme (the “bottom”) of the F proteintrimer; by locating the genetic fusion at this point, the majority ofthe F protein structure will be displayed and accessible on thenanostructure exterior. In a further embodiment, the nanostructurescomprise one or more copies of a fusion protein comprising at least twodomains—a paramyxovirus and/or pneumovirus F protein, or an antigenicfragment thereof, and a trimeric assembly domain (i.e.: each firstassembly is a homotrimer of the first polypeptide)—and one or morecopies of a second oligomeric block (i.e.: each second assembly is anoligomer of two or more copies of the second polypeptide). In anotherembodiment, the first and or second polypeptides may be modified topermit the one or more paramyxovirus and/or pneumovirus F proteins, orantigenic fragments thereof, to be covalently linked to the first and/orsecond polypeptides. In one non-limiting example, the first and/orsecond polypeptides can be modified, such as by introduction of variouscysteine residues at defined positions to facilitate linkage one or moreparamyxovirus and/or pneumovirus F proteins, or antigenic fragmentsthereof.

In other embodiments, the one or more paramyxovirus and/or pneumovirus Fproteins, or antigenic fragments thereof are attached to the first orsecond polypeptides via any suitable technique, including but notlimited to covalent chemical cross-linking (via any suitablecross-linking technique) and non-covalent attachment includingengineered electrostatic interactions.

Trimeric Assembly Domains

In one embodiment of a trimeric assembly that comprises a trimericparamyxovirus and/or pneumovirus F protein, or antigenic fragmentsthereof, the paramyxovirus and/or pneumovirus F protein, or antigenicfragment thereof is genetically fused to the first polypeptides thatself-assemble into the trimeric assembly. The trimeric assemblycomprises a protein-protein interface that induces three copies of thefirst polypeptides to self-associate to form trimeric building blocks.Each copy of the first polypeptides further comprises a surface-exposedinterface that interacts with a complementary surface-exposed interfaceon a second assembly domain. As described in King et al. (Nature 510,103-108, 2014), Bale et al. (Science 353, 389-394, 2016), and patentpublications WO2014124301 A1 and US20160122392 A1, the complementaryprotein-protein interface between the trimeric assembly domain andsecond assembly domain drives the assembly of multiple copies of thetrimeric assembly domain and second assembly domain to a targetnanostructure. In some embodiments, each copy of the trimeric assemblydomains of the nanostructure bears a paramyxovirus and/or pneumovirus Fproteins, or antigenic fragment thereof, as a genetic fusion; thesenanostructures display the F proteins at full valency. In otherembodiments, the nanostructures of the invention comprise one or morecopies of trimeric assembly domains bearing paramyxovirus and/orpneumovirus F proteins, or antigenic fragments thereof as geneticfusions as well as one or more trimeric assembly domains that do notbear F proteins as genetic fusions; these nanostructures display the Fproteins at partial valency. The trimeric assembly domain can be anypolypeptide sequence that forms a trimer and interacts with a secondassembly domain to drive assembly to a target nanostructure.

In one specific embodiment, the first polypeptides comprise polypeptideshaving at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%,98%, 99%, or 100% identity along their full length to the amino acidsequence of T33-31A (SEQ ID NO:51) and the second polypeptides comprisepolypeptides having at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%,95%, 96%, 97%, 98%, 99%, or 100% identity along their full length to theamino acid sequence of T33-09B/T33-31B (SEQ ID NO:44) (residues inparentheses are optional)

T33-31A (SEQ ID NO: 51)(M)EEVVLITVPSALVAVKIAHALVEERLAACVNIVPGLTSIYREEGSVVSDHELLLLVKTTTDAFPKLKERVKELHPYEVPEIVALPIAEGNREYLDWL RENTG >T33-31B(SEQ ID NO: 44) (M)VRGIRGAITVEEDTPAAILAATIELLLKMLEANGIQSYEELAAVIFTVTEDLTSAFPAEAARLIGMHRVPLLSAREVPVPGSLPRVIRVLALWNTDTPQDRVRHVYLNEAVRLRPDLESAQ

In another specific embodiment, the first polypeptides comprisepolypeptides having at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%,95%, 96%, 97%, 98%, 99%, or 100% identity along their full length to theamino acid sequence of T33-15A (SEQ ID NO:45) and the secondpolypeptides comprise polypeptides having at least 75%, 80%, 85%, 90%,91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity alongtheir full length to the amino acid sequence of T33-15B (SEQ ID NO:46).

In various further specific embodiments, the first polypeptides comprisepolypeptides having at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%,95%, 96%, 97%, 98%, 99%, or 100% identity along their full length to theamino acid sequence of a polypeptides selected from the group consistingof 153-50A (SEQ ID NO:7), 153-50A.1 (SEQ ID NO:29), 153-50A.1NegT2 (SEQID NO:30), and 153-50A.1PosT1 (SEQ ID NO:31), and the secondpolypeptides comprise polypeptides having at least 75%, 80%, 85%, 90%,91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity alongtheir full length to the amino acid sequence of a polypeptide selectedfrom the group consisting of 153-50B (SEQ ID NO:8), 153-50B.1 (SEQ IDNO:32), I53-50B.1NegT2 (SEQ ID NO:33), and I53-50B.4PosT1 (SEQ IDNO:34).

In another specific embodiment, the first polypeptides comprisepolypeptides having at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%,95%, 96%, 97%, 98%, 99%, or 100% identity along their full length to theamino acid sequence of I32-28A (SEQ ID NO:21) and the secondpolypeptides comprise polypeptides having at least 75%, 80%, 85%, 90%,91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity alongtheir full length to the amino acid sequence of 132-28B (SEQ ID NO:22).

The nanostructures of the invention display multiple copies (i.e.: 2, 3,or more) of one or more paramyxovirus and/or pneumovirus F proteins, orantigenic fragments thereof, on an exterior of the nanostructure.Exemplary paramyxovirus and/or pneumovirus include, but are not limitedto, respiratory syncytial virus (RSV) and Human metapneumovirus (hMPV).(C. L. Afonso et al., Taxonomy of the order Mononegavirales: update2016. Arch. Virol. 161, 2351-2360 (2016)).

As used herein, “on an exterior of the nanostructure” means that anantigenic portion of the one or more paramyxovirus and/or pneumovirus Fproteins, or antigenic fragments thereof, must be accessible for bindingby B cell receptors, antibodies, or antibody fragments and not buriedwithin the nanostructure.

The one or more paramyxovirus and/or pneumovirus F proteins, orantigenic fragments thereof, may comprise any suitable native Fproteins, post-fusion, or pre-fusion (preF) antigens, or mutants thereofcapable of inducing an immune response that will generate antibodiesthat bind to paramyxovirus and/or pneumovirus F proteins. Ananostructure may display more than one F protein; thus, in someembodiments the one or more paramyxovirus and/or pneumovirus F proteins,or antigenic fragments thereof comprise 1, 2, 3, 4, or more F proteinsor antigenic fragments thereof. In one embodiment, the one or moreparamyxovirus and/or pneumovirus F proteins, or antigenic fragmentsthereof may be as defined in patent publication number US 2016/0046675A1. In some embodiments, the one or more paramyxovirus and/orpneumovirus F proteins, or antigenic fragments thereof, are selectedfrom the group consisting of SEQ ID NOS: 1-350, 370-382, 389-693,698-1026, 1429-1442, 1456-1468, and 1474-1478 as disclosed in USpublished patent application 2016/0046675. In other embodiments, the oneor more paramyxovirus and/or pneumovirus F proteins, or antigenicfragments thereof may be as defined in WO2012158613, US 20160102123,US20140141037, WO2014079842, WO2014160463, US20140271699, EP2970393,WO2014174018, US20140271699, US20160176932, US20160122398, WO2017040387,WO2017109629, WO2017172890, WO2017207477, Krarup et al. (2015) NatureCommunications 6:8143, and WO2017207480.

In a specific embodiment, the one or more paramyxovirus and/orpneumovirus F proteins, or antigenic fragments thereof, comprise apolypeptide having at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%,96%, 97%, 98%, 99%, or 100% identity along its full length to the aminoacid sequence of DS-Cav1 shown below (residues in parentheses areoptional; note that the N-terminal residues in parentheses are cleavedfrom the protein during secretion—the mature N terminus begins withQNITEEF . . . (SEQ ID NO:52)). DS-Cav1 comprises a prefusion-stabilizedform of the fusion (F) glycoprotein, which elicits improved protectiveresponses against respiratory syncytial virus (RSV) in mice and macaquescompared to postfusion RSV F (McLellan et al. (2013) Science 342:592-8).

DS-Cav1 (SEQ ID NO: 53):(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRKRRFLGFLLGVGSAIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEK INQSLAFIR(KSDELL)

In other embodiments, the F protein may comprise a polypeptide having atleast 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%,or 100% identity along its full length to a polypeptide selected from:

RSVF sc9-10DS-Cav1 A149C Y458C (SEQ ID NO: 61)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATGSGSAICSGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTNEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSRTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYCVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIR(KSDELL) sc9-10 DS-Cav1 A149C Y458CS46G K465Q S215P E92D (SEQ ID NO: 62)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLGAL  RTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTDLQLLMQSTPATGSGSAICSGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSIPNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSRTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYCVNKQEGQSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIR(KSDELL)

SEQ ID NO:61-62 represent second-generation stabilized DS-Cav1immunogens; mutations relative to DS-Cav1 are noted and it should benoted that the present disclosure contemplates the use of DS-Cav1mutants that differ by a single one of the noted amino acidsubstitutions in SEQ ID NO:61 or 62 above, or two or more of the aminoacid substitutions noted. In other embodiments, the F protein maycomprise one or more of the following, each of which may additionallyinclude 1, 2, or more of the noted amino acid substitutions in SEQ IDNO:61 or 62 above:

RSV F SC-DM (N67I, S215P) (SEQ ID NO: 63)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKKIKCNGTDAKIKLIKQELDKYKNAVTELQLLMQSTPATNNQARGSGSGRSLGFLLGVGSAIASGVAVSKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTSKVLDLKNYIDKQLLPIVNKQSCSIPNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSINSIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIR(KSDELLSAIGGYIPEAPRDGQAYVRKDGEWVL LSTFL)SC-TM (N67I, 5215P, and E487Q) (SEQ ID NO: 64)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKKIKCNGTDAKIKLIKQELDKYKNAVTELQLLMQSTPATNNQARGSGSGRSLGFLLGVGSAIASGVAVSKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTSKVLDLKNYIDKQLLPIVNKQSCSIPNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMSIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINEYDPLVFPSDQFDASISQVNEKINQSLAFIR(KSDELLSAIGGYIPEAPRDGQAYVRKDGEWVL LSTFL)HMPV F protein, strain CAN97-83 (A2) (SEQ ID NO: 65)(MSWKVVIIFSLLITPQHG)LKESYLEESCSTITEGYLSVLRTGWYTNVFTLEVGDVENLTCSDGPSLIKTELDLTKSALRELKTVSADQLAREEQIENPRQSRFVLGAIALGVATAAAVTAGVAIAKTIRLESEVTAIKNALKTTNEAVSTLGNGVRVLATAVRELKDFVSKNLTRAINKNKCDIDDLKMAVSFSQFNRRFLNVVRQFSDNAGITPAISLDLMTDAELARAVSNMPTSAGQIKLMLENRAMVRRKGFGILIGVYGSSVIYMVQLPIFGVIDTPCWIVKAAPSCSGKKGNYACLLREDQGWYCQNAGSTVYYPNEKDCETRGDHVFCDTAAGINVAEQSKECNINISTTNYPCKVSTGRHPISMVALSPLGALVACYKGVSCSIGSNRVGIIKQLNKGCSYITNQDADTVTIDNTVYQLSKVEGEQHVIKGRPVSSSFDPIKFPEDQFNVALDQVFENIENSQALVDQSNRILSSAEKGNTGHMPV F with A113C, A339C, T160F, I177L (SEQ ID NO: 66)(MSWKVVIIFSLLITPQHG)LKESYLEESCSTITEGYLSVLRTGWYTNVFTLEVGDVENLTCSDGPSLIKTELDLTKSALRELKTVSADQLAREEQIENPRQSRFVLGAIALGVCTAAAVTAGVAIAKTIRLESEVTAIKNALKTTNEAVSTLGNGVRVLAFAVRELKDFVSKNLTRALNKNKCDIDDLKMAVSFSQFNRRFLNVVRQFSDNAGITPAISLDLMTDAELARAVSNMPTSAGQIKLMLENRAMVRRKGFGILIGVYGSSVIYMVQLPIFGVIDTPCWIVKAAPSCSGKKGNYACLLREDQGWYCQNAGSTVYYPNEKDCETRGDHVFCDTACGINVAEQSKECNINISTTNYPCKVSTGRHPISMVALSPLGALVACYKGVSCSIGSNRVGIIKQLNKGCSYITNQDADTVTIDNTVYQLSKVEGEQHVIKGRPVSSSFDPIKFPEDQFNVALDQVFENIENSQALVDQSNRILSSAEKGNTGHMPV F with A113C, A120C, A339C, T160F, I177L, and Q426C (SEQ ID NO: 67)(MSWKVVIIFSLLITPQHG)LKESYLEESCSTITEGYLSVLRTGWYTNVFTLEVGDVENLTCSDGPSLIKTELDLTKSALRELKTVSADQLAREEQIENPRQSRFVLGAIALGVCTAAAVTCGVAIAKTIRLESEVTAIKNALKTTNEAVSTLGNGVRVLAFAVRELKDFVSKNLTRALNKNKCDIDDLKMAVSFSQFNRRFLNVVRQFSDNAGITPAISLDLMTDAELARAVSNMPTSAGQIKLMLENRAMVRRKGFGILIGVYGSSVIYMVQLPIFGVIDTPCWIVKAAPSCSGKKGNYACLLREDQGWYCQNAGSTVYYPNEKDCETRGDHVFCDTACGINVAEQSKECNINISTTNYPCKVSTGRHPISMVALSPLGALVACYKGVSCSIGSNRVGIIKQLNKGCSYITNQDADTVTIDNTVYCLSKVEGEQHVIKGRPVSSSFDPIKFPEDQFNVALDQVFENIENSQALVDQSNRILSSAEKGNTGHMPV F>AAK62968.2 fusion protein [Human metapneumovirus](SEQ ID NO: 101)(MSWKVVIIFSLLITPQHG)LKESYLEESCSTITEGYLSVLRTGWYTNVFTLEVGDVENLTCADGPSLIKTELDLTKSALRELRTVSADQLAREEQIENPRQSRFVLGAIALGVATAAAVTAGVAIAKTIRLESEVTAIKNALKKTNEAVSTLGNGVRVLATAVRELKDFVSKNLTRAINKNKCDIADLKMAVSFSQFNRRFLNVVRQFSDNAGITPAISLDLMTDAELARAVSNMPTSAGQIKLMLENRAMVRRKGFGFLIGVYGSSVIYMVQLPIFGVIDTPCWIVKAAPSCSGKKGNYACLLREDQGWYCQNAGSTVYYPNEKDCETRGDHVFCDTAAGINVAEQSKECNINISTTNYPCKVSTGRHPISMVALSPLGALVACYKGVSCSIGSNRVGIIKQLNKGCSYITNQDADTVTIDNTVYQLSKVEGEQHVIKGRPVSSSFDPVKFPEDQFNVALDQVFESIENSQALVDQSNRILSSAEKGNTG 115-BV (A185P) (SEQ ID NO: 68)(MSWKVVIIFSLLITPQHG)LKESYLEESCSTITEGYLSVLRTGWYTNVFTLEVGDVENLTCADGPSLIKTELDLTKSALRELRTVSADQLAREEQIENPRRRRFVLGAIALGVATAAAVTAGVAIAKTIRLESEVTAIKNALKKTNEAVSTLGNGVRVLATAVRELKDFVSKNLTRAINKNKCDIPDLKMAVSFSQFNRRFLNVVRQFSDNAGITPAISLDLMTDAELARAVSNMPTSAGQIKLMLENRAMVRRKGFGILIGVYGSSVIYMVQLPIFGVIDTPCWIVKAAPSCSEKKGNYACLLREDQGWYCQNAGSTVYYPNEKDCETRGDHVFCDTAAGINVAEQSKECNINISTTNYPCKVSTGRHPISMVALSPLGALVACYKGVSCSIGSNRVGIIKQLNKGCSYITNQDADTVTIDNTVYQLSKVEGEQHVIKGRPVSSSFDPVKFPEDQFNVALDQVFESIENSQALVDQSNRILSSAEKGNT(SGRENLYFQGGGGSGYIPEAPRDGQAYVRKDGEWVLLSTFLGGIEGRHHHHHH)

In other embodiments, the one or more paramyxovirus and/or pneumovirus Fproteins, or antigenic fragments thereof, may comprise a polypeptidehaving at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%,98%, 99%, or 100% identity along its full length to an RSV F protein ormutant thereof selected from the group consisting of SEQ ID NO:53 and61-64, wherein the polypeptide includes one or more of the followingresidues: 671, 149C, 458C, 46G, 465Q, 215P, 92D, and 487Q.

In other embodiments, the one or more paramyxovirus and/or pneumovirus Fproteins, or antigenic fragments thereof, may comprise a polypeptidehaving at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%,98%, 99%, or 100% identity along its full length to an MPV F protein ormutant thereof selected from the group consisting of SEQ ID NO:65-68 and101, wherein the polypeptide includes one or more of the followingresidues: 113C, 120C, 339C, 160F, 177L, 185P, and 426C.

Linker Between F Proteins and Trimeric Assembly Domains and GeometricRequirements

In the nanostructures of the invention, the F protein and the trimericassembly domain may be genetically fused such that they are both presentin a single polypeptide. Preferably, the linkage between the F proteinand the trimeric assembly domain allows the F protein, or antigenicfragment thereof, to be displayed on the exterior of the nanostructuresof the invention. As such, the point of connection to the trimericassembly domain should be on the exterior of the nanostructure formed bythe trimeric assembly domain and the second assembly domain in theabsence of any F protein. As will be understood by those of skill in theart, a wide variety of polypeptide sequences can be used to link theparamyxovirus and/or pneumovirus F proteins, or antigenic fragmentsthereof and the trimeric assembly domain. These polypeptide sequencesare referred to as linkers. Any suitable linker can be used; there is noamino acid sequence requirement to serve as an appropriate linker. Thereis no requirement that the linker impose a rigid relative orientation ofthe F protein or antigenic fragment thereof to the trimeric assemblydomain beyond enabling the F protein or antigenic fragment thereof to bedisplayed on the exterior of the nanostructures of the invention. Insome embodiments, the linker includes additional trimerization domains(e.g., the foldon domain of T4 fibritin) that assist in stabilizing thetrimeric form of the F protein.

T4 fibritin foldon domain (optional in the linker region)(SEQ ID NO: 54) GYIPEAPRDGQAYVRKDGEWVLLSTFL

In other embodiments, the linker may comprise a Gly-Ser linker (i.e.: alinker consisting of glycine and serine residues) of any suitablelength. In various embodiments, the Gly-Ser linker may be 3, 4, 5, 6, 7,8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or more amino acids inlength. In various embodiments, the Gly-Ser linker may comprise orconsist of the amino acid sequence of GSGGSGSGSGGSGSG (SEQ ID NO:55),GGSGGSGS (SEQ ID NO:56) or GSGGSGSG (SEQ ID NO:57).

In further embodiments the linker may comprise a helical extensiondomain that may serve to extend the N-terminal helix of the firstpolypeptide, when expressed as a fusion polypeptide with the one or moreparamyxovirus and/or pneumovirus F proteins, or antigenic fragmentsthereof, so that it is located at the exterior of the nanostructuresurface. The helical extension may be present in combination with theother linker components described herein, or may be absent. The helicalextension may be of any suitable length (i.e.: 7, 8, 9, 10, 11, 12, ormore amino acids) and comprise any suitable primary amino acid sequence.In one embodiment, the helical extension may comprise or consist of theamino acid sequence EKAAKAEEAAR (SEQ ID NO:58).

Thus, in various non-limiting embodiments in which the F protein ispresent as a fusion protein with the first polypeptide and a linker isused, the F protein-linker sequence may comprise the following(exemplified by DS-Cav1 as the F protein in these non-limitingembodiments). Residues in parentheses are optional and the amino acidsequence MELLILKANAITTILTAVTFCFASG (SEQ ID NO:59) represents theN-terminal DS-Cav1 signal peptide that is cleaved during processing:

DS-Cav1-foldon (SEQ ID NO: 60):(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRKRRFLGFLLGVGSAIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRKSDELLGYIPEAPRDGQAYVRKDGEWILLSTFL

In various further embodiments, the first polypeptides comprise orconsist of fusion polypeptides of first polypeptides fused to an Fprotein, where the fusion protein has a sequence selected from thefollowing (optional residues in parentheses): DS-Cav1-foldon-T33-31A(SEQ ID NO:69)

DS-Cav1-foldon-T33-31A (SEQ ID NO: 69)(MELLILKANVIATILTAVTFCFASS)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRKRRELGELLGVGSAIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRKSDELLGYIPEAPRDGQAYVRKDGEWVLLSTFLGGSMEEVVLITVPSALVAVKIAHALVEERLAACVNIVPGLTSIYREEGSVVSDHELLLLVKTTTDAFPKLKERVKELHPYEVPEIVALPIAEGNREYLDWLRENTGDS-Cav1-T33-31A (SEQ ID NO: 70)(MELLILKANVIATILTAVTFCFASS)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRKRRFLGFLLGVGSAIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRKSDELLGGSMEEVVLITVPSALVAVKIAHALVEERLAACVNIVPGLTSIYREEGSVVSDHELLLLVKTTTDAFPKLKERVKELHPYEVPEIVALPIAEGNREYLDWLRENTG DS-Cav1-foldon-T33-15B(SEQ ID NO: 71)(MELLILKANVIATILTAVTFCFASS)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRKRRFLGFLLGVGSAIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRKSDELLGYIPEAPRDGQAYVRKDGEWVLLSTFLGGSMVRGIRGAITVNSDTPTSIIIATILLLEKMLEANGIQSYEELAAVIFTVTEDLTSAFPAEAARQIGMHRVPLLSAREVPVPGSLPRVIRVLALWNTDTPQDRVRHVYLSEAVRLRPDLESAQ DS-Cav1-T33-15B (SEQ ID NO: 72)(MELLILKANVIATILTAVTFCFASS)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRKRRFLGFLLGVGSAIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRKSDELLGGSMVRGIRGAITVNSDTPTSIIIATILLLEKMLEANGIQSYEELAAVIFTVTEDLTSAFPAEAARQIGMHRVPLLSAREVPVPGSLPRVIRVLALWNTDTPQDRVRHVYLSEAVRLRPDLESAQDS-Cav1-foldon-I53-50A (SEQ ID NO: 73)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRKRRFLGFLLGVGSAIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRGYIPEAPRDGQAYVRKDGEWVLLSTFLGSGSHHHHHHHHGGSGGSGSEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVEYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTE DS-Cav1-I53-50A(SEQ ID NO: 74)(MELLILKANVIATILTAVTFCFASS)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRKRRFLGFLLGVGSAIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRGGSGGSGSEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTE DS-Cav1-I32-28A (SEQ ID NO: 75)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRKRRFLGFLLGVGSAIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRKSDELLGGSGGSGSDDARIAAIGDVDELNSQIGVLLAEPLPDDVRAALSAIQHDLFDLGGELCIPGHAAITEDHLLRLALWLVHYNGQLPPLEEFILPGGARGAALAHVCRTVCRRAERSIKALGASEPLNIAPAAYVNLLSDLLFVLARVLNRAAGGADVLWDRTRAH DS-Cav1-8GS-HelExt-I53-50A (F10)(SEQ ID NO: 76)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRKRRFLGFLLGVGSAIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRGSGGSGSGEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTE DS-Cav1-foldon-15GS-HelExt-I53-50A (F14)(SEQ ID NO: 77)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRKRRFLGFLLGVGSAIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIENPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRGYIPEAPRDGQAYVRKDGEWVLLSTFLGSGGSGSGSGGSGSGEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTEHMPV F wt_CAN97-83 strain-I53-50A (SEQ ID NO: 78)(MSWKVVIIFSLLITPQHG)LKESYLEESCSTITEGYLSVLRTGWYTNVFTLEVGDVENLTCSDGPSLIKTELDLTKSALRELKTVSADQLAREEQIENPRQSRFVLGAIALGVATAAAVTAGVAIAKTIRLESEVTAIKNALKTTNEAVSTLGNGVRVLATAVRELKDFVSKNLTRAINKNKCDIDDLKMAVSFSQFNRRFLNVVRQFSDNAGITPAISLDLMTDAELARAVSNMPTSAGQIKLMLENRAMVRRKGFGILIGVYGSSVIYMVQLPIFGVIDTPCWIVKAAPSCSGKKGNYACLLREDQGWYCQNAGSTVYYPNEKDCETRGDHVFCDTAAGINVAEQSKECNINISTTNYPCKVSTGRHPISMVALSPLGALVACYKGVSCSIGSNRVGIIKQLNKGCSYITNQDADTVTIDNTVYQLSKVEGEQHVIKGRPVSSSFDPIKFPEDQFNVALDQVFENIENSQALVDQSNRILSSAEKGNTGFIIVIILIAVLGSSMILVSIFIIIKKTKKPTGAPPELSGVTNNGFIPHSGSGSHHHHHHHHGGSGGSGSEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTEHMPV F A113C_A339C_T160F_1177L-I53-50A (SEQ ID NO: 79)(MSWKVVIIFSLLITPQHG)LKESYLEESCSTITEGYLSVLRTGWYTNVFTLEVGDVENLTCSDGPSLIKTELDLTKSALRELKTVSADQLAREEQIENPRQSRFVLGAIALGVCTAAAVTAGVAIAKTIRLESEVTAIKNALKTTNEAVSTLGNGVRVLAFAVRELKDFVSKNLTRALNKNKCDIDDLKMAVSFSQFNRRFLNVVRQFSDNAGITPAISLDLMTDAELARAVSNMPTSAGQIKLMLENRAMVRRKGFGILIGVYGSSVIYMVQLPIFGVIDTPCWIVKAAPSCSGKKGNYACLLREDQGWYCQNAGSTVYYPNEKDCETRGDHVFCDTACGINVAEQSKECNINISTTNYPCKVSTGRHPISMVALSPLGALVACYKGVSCSIGSNRVGIIKQLNKGCSYITNQDADTVTIDNTVYQLSKVEGEQHVIKGRPVSSSFDPIKFPEDQFNVALDQVFENIENSQALVDQSNRILSSAEKGNTGGSGSHHHHHHHHGGSGGSGSEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTE HMPV F A113C_A339C_T160F_I177L_A120C, Q426Cmutations-I53-50A (SEQ ID NO: 80)(MSWKVVIIFSLLITPQHG)LKESYLEESCSTITEGYLSVLRTGWYTNVFTLEVGDVENLTCSDGPSLIKTELDLTKSALRELKTVSADQLAREEQIENPRQSRFVLGAIALGVCTAAAVTCGVAIAKTIRLESEVTAIKNALKTTNEAVSTLGNGVRVLAFAVRELKDFVSKNLTRALNKNKCDIDDLKMAVSFSQFNRRFLNVVRQFSDNAGITPAISLDLMTDAELARAVSNMPTSAGQIKLMLENRAMVRRKGFGILIGVYGSSVIYMVQLPIFGVIDTPCWIVKAAPSCSGKKGNYACLLREDQGWYCQNAGSTVYYPNEKDCETRGDHVFCDTACGINVAEQSKECNINISTTNYPCKVSTGRHPISMVALSPLGALVACYKGVSCSIGSNRVGIIKQLNKGCSYITNQDADTVTIDNTVYCLSKVEGEQHVIKGRPVSSSFDPIKFPEDQFNVALDQVFENIENSQALVDQSNRILSSAEKGNTGGSGSHHHHHHHHGGSGGSGSEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVEYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTE sc-DS2-I53-50A (SEQ ID NO: 81)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATGSGSCIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYCVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAE'RGSGSHHHHHHHHGGSGGSGSEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTE tc-DS2-I53-50A(SEQ ID NO: 82)(MELLILKANAITTILTAVTFCEASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRKRRFLGELLGVGSCIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTEKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYCVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRGSGSHHHHHHHHGGSGGSGSEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVEYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTE DS-Cav1-12GS-HelExt-I53-50A (F11)(SEQ ID NO: 83)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRKRRFLGELLGVGSAIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRGSGGSGSGSGGSEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTE DS-Cav1-16GS-HelExt-I53-50A (F12) (SEQ ID NO: 84)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRKRRFLGELLGVGSAIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRGSGGSGSGSGGSGSGGEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTE DS-Cav1-foldon-10GS-HelExt-I53-50A (F13(SEQ ID NO: 85)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRKRRFLGFLLGVGSAIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRGYIPEAPRDGQAYVRKDGEWVLLSTFLGSGGSGSGSGEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEElSQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTEDS-Cav1-foldon-20GS-HelExt-I53-50A (F15) (SEQ ID NO: 86)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRKRRFLGFLLGVGSAIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRGYIPEAPRDGQAYVRKDGEWVLLSTFLGSGGSGSGSGGSGSGGSSGSEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTEsc9-10 DS-Cav1 A149C Y458C-foldon-I53-50A embodiment (SEQ ID NO: 87)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATGSGSAICSGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSRTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYCVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIR(KSDELL)GYIPEAPRDGQAYVRKDGEWVLLSTFLGSGSHHHHHHHHGGSGGSGSEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTEsc9-10DS-Cav1 A149C Y458C-I53-50A-F10 embodiment (SEQ ID NO: 88)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATGSGSAICSGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSRTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYCVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIR(KSDELL)GSGGSGSGEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTEsc9-10 DS-Cav1 A149C Y458C S46G K465Q S215P E92D-foldon-I53-50A embodiment (SEQ ID NO: 89)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLGALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTDLQLLMQSTPATGSGSAICSGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSIPNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSRTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYCVNKQEGQSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIR(KSDELL)GYIPEAPRDGQAYVRKDGEWVLLSTFLGSGSHHHHHHHHGGSGGSGSEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTEsc9-10DS-Cav1 A149C Y458C S46G K465Q S215P E92D-I53- 50A-F10 embodiment(SEQ ID NO: 90)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLGALRTGWYTSVITIELSNIKENKCNGTDAKVKLIKQELDKYKNAVTDLQLLMQSTPATGSGSAICSGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSIPNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSRTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYCVNKQEGQSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIR(KSDELL)GSGGSGSGEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKEVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTESC-DM (N67I, S215P)-foldon-I53-50A embodiment (SEQ ID NO: 91)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKKIKCNGTDAKIKLIKQELDKYKNAVTELQLLMQSTPATNNQARGSGSGRSLGFLLGVGSAIASGVAVSKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTSKVLDLKNYIDKQLLPIVNKQSCSIPNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMSIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIR(KSDELL)GYIPEAPRDGQAYVRKDGEWVLLSTFLGSGSHHHHHHHHGGSGGSGSEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTESC-DM (N67I, S215P)-I53-50A-F10 embodiment (SEQ ID NO: 92)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKKIKCNGTDAKIKLIKQELDKYKNAVTELQLLMQSTPATNNQARGSGSGRSLGFLLGVGSAIASGVAVSKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTSKVLDLKNYIDKQLLPIVNKQSCSIPNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMSIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIR(KSDELL)GSGGSGSGEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRG CTESC-TM (N67I, 5215P, and E487Q)-foldon-I53-50A embodiment (SEQ ID NO: 93)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNISKIKCNGTDAKIKLIKQELDKYKNAVTELQLLMQSTPATNNQARGSGSGRSLGFLLGVGSAIASGVAVSKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTSKVLDLKNYIDKQLLPIVNKQSCSIPNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMSIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDQFDASISQVNEKINQSLAFIR(KSDELL)GYIPEAPRDGQAYVRKDGEWVLLSTFLGSGSHHHHHHHHGGSGGSGSEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTESC-TM (N67I, S215P, and E487Q)-I53-50A-F10 embodiment (SEQ ID NO: 94)(MELLILKANAITTILTAVTFCFASG)QNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNISKIKCNGTDAKIKLIKQELDKYKNAVTELQLLMQSTPATNNQARGSGSGRSLGFLLGVGSAIASGVAVSKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTSKVLDLKNYIDKQLLPIVNKQSCSIPNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSINSIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYVKGEPIINFYDPLVFPSDQFDASISQVNEKINQSLAFIR(KSDELL)GSGGSGSGEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRG CTEHMPV-F with A113C, A339C, T160F, I177L-foldon-I53-50A embodiment(SEQ ID NO: 95)(MSWKVVIIFSLLITPQHG)LKESYLEESCSTITEGYLSVLRTGWYTNVFTLEVGDVENLTCSDGPSLIKTELDLTKSALRELKTVSADQLAREEQIENPRQSRFVLGAIALGVCTAAAVTAGVAIAKTIRLESEVTAIKNALKTTNEAVSTLGNGVRVLAFAVRELKDFVSKNLTRALNKNKCDIDDLKMAVSFSQFNRRFLNVVRQFSDNAGITPAISLDLMTDAELARAVSNMPTSAGQIKLMLENRAMVRRKGFGILIGVYGSSVIYMVQLPIFGVIDTPCWIVKAAPSCSGKKGNYACLLREDQGWYCQNAGSTVYYPNEKDCETRGDHVFCDTACGINVAEQSKECNINISTTNYPCKVSTGRHPISMVALSPLGALVACYKGVSCSIGSNRVGIIKQLNKGCSYITNQDADTVTIDNTVYQLSKVEGEQHVIKGRPVSSSFDPIKFPEDQFNVALDQVFENIENSQALVDQSNRILSSAEKGNTGGYIPEAPRDGQAYVRKDGEWVLLSTFLGSGSHHHHHHHHGGSGGSGSEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTEHMPV-F with A113C, A339C, T160F, I177L-I53-50A F10 embodiment(SEQ ID NO: 96)(MSWKVVIIFSLLITPQHG)LKESYLEESCSTITEGYLSVLRTGWYTNVFTLEVGDVENLTCSDGPSLIKTELDLTKSALRELKTVSADQLAREEQIENPRQSRFVLGAIALGVCTAAAVTAGVAIAKTIRLESEVTAIKNALKTTNEAVSTLGNGVRVLAFAVRELKDFVSKNLTRALNKNKCDIDDLKMAVSFSQFNRRFLNVVRQFSDNAGITPAISLDLMTDAELARAVSNMPTSAGQIKLMLENRAMVRRKGFGILIGVYGSSVIYMVQLPIFGVIDTPCWIVKAAPSCSGKKGNYACLLREDQGWYCQNAGSTVYYPNEKDCETRGDHVFCDTACGINVAEQSKECNINISTTNYPCKVSTGRHPISMVALSPLGALVACYKGVSCSIGSNRVGIIKQLNKGCSYITNQDADTVTIDNTVYQLSKVEGEQHVIKGRPVSSSFDPIKFPEDQFNVALDQVFENIENSQALVDQSNRILSSAEKGNTGGSGGSGSGEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTEHMPV-F with A113C, A120C, A339C, T160F, I177L, andQ426C-foldon-I53-50A embodiment (SEQ ID NO: 97)(MSWKVVIIFSLLITPQHG)LKESYLEESCSTITEGYLSVLRTGWYTNVFTLEVGDVENLTCSDGPSLIKTELDLTKSALRELKTVSADQLAREEQIENPRQSRFVLGAIALGVCTAAAVTCGVAIAKTIRLESEVTAIKNALKTTNEAVSTLGNGVRVLAFAVRELKDFVSKNLTRALNKNKCDIDDLKMAVSFSQFNRRFLNVVRQFSDNAGITPAISLDLMTDAELARAVSNMPTSAGQIKLMLENRAMVRRKGFGILIGVYGSSVIYMVQLPIFGVIDTPCWIVKAAPSCSGKKGNYACLLREDQGWYCQNAGSTVYYPNEKDCETRGDHVFCDTACGINVAEQSKECNINISTTNYPCKVSTGRHPISMVALSPLGALVACYKGVSCSIGSNRVGIIKQLNKGCSYITNQDADTVTIDNTVYCLSKVEGEQHVIKGRPVSSSFDPIKFPEDQFNVALDQVFENIENSQALVDQSNRILSSAEKGNTGGYIPEAPRDGQAYVRKDGEWVLLSTFLGSGSHHHHHHHHGGSGGSGSEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTEHMPV-F with A113C, A120C, A339C, T160F, I177L, and Q426C-F10 embodiment(SEQ ID NO: 98)(MSWKVVIIFSLLITPQHG)LKESYLEESCSTITEGYLSVLRTGWYTNVFTLEVGDVENLTCSDGPSLIKTELDLTKSALRELKTVSADQLAREEQIENPRQSRFVLGAIALGVCTAAAVTCGVAIAKTIRLESEVTAIKNALKTTNEAVSTLGNGVRVLAFAVRELKDFVSKNLTRALNKNKCDIDDLKMAVSFSQFNRRFLNVVRQFSDNAGITPAISLDLMTDAELARAVSNMPTSAGQIKLMLENRAMVRRKGFGILIGVYGSSVIYMVQLPIFGVIDTPCWIVKAAPSCSGKKGNYACLLREDQGWYCQNAGSTVYYPNEKDCETRGDHVFCDTACGINVAEQSKECNINISTTNYPCKVSTGRHPISMVALSPLGALVACYKGVSCSIGSNRVGIIKQLNKGCSYITNQDADTVTIDNTVYCLSKVEGEQHVIKGRPVSSSFDPIKFPEDQFNVALDQVFENIENSQALVDQSNRILSSAEKGNTGGSGGSGSGEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTEHMPV-F 115-BV (A185P)-foldon-I53-50A embodiment (SEQ ID NO: 99)(MSWKVVIIFSLLITPQHG)LKESYLEESCSTITEGYLSVLRTGWYTNVFTLEVGDVENLTCADGPSLIKTELDLTKSALRELRTVSADQLAREEQIENPRRRRFVLGAIALGVATAAAVTAGVAIAKTIRLESEVTAIKNALKKTNEAVSTLGNGVRVLATAVRELKDFVSKNLTRAINKNKCDIPDLKMAVSFSQFNRRFLNVVRQFSDNAGITPAISLDLMTDAELARAVSNMPTSAGQIKLMLENRAMVRRKGFGILIGVYGSSVIYMVQLPIFGVIDTPCWIVKAAPSCSEKKGNYACLLREDQGWYCQNAGSTVYYPNEKDCETRGDHVFCDTAAGINVAEQSKECNINISTTNYPCKVSTGRHPISMVALSPLGALVACYKGVSCSIGSNRVGIIKQLNKGCSYITNQDADTVTIDNTVYQLSKVEGEQHVIKGRPVSSSFDPVKFPEDQFNVALDQVFESIENSQALVDQSNRILSSAEKGNTGYIPEAPRDGQAYVRKDGEWVLLSTFLGSGSHHHHHHHHGGSGGSGSEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEWGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTEHMPV-F 115-BV (A185P)-I53-50A-F10 embodiment (SEQ ID NO: 100)(MSWKVVIIFSLLITPQHG)LKESYLEESCSTITEGYLSVLRTGWYTNVFTLEVGDVENLTCADGPSLIKTELDLTKSALRELRTVSADQLAREEQIENPRRRRFVLGAIALGVATAAAVTAGVAIAKTIRLESEVTAIKNALKKTNEAVSTLGNGVRVLATAVRELKDFVSKNLTRAINKNKCDIPDLKMAVSFSQFNRRFLNVVRQFSDNAGITPAISLDLMTDAELARAVSNMPTSAGQIKLMLENRAMVRRKGFGILIGVYGSSVIYMVQLPIFGVIDTPCWIVKAAPSCSEKKGNYACLLREDQGWYCQNAGSTVYYPNEKDCETRGDHVFCDTAAGINVAEQSKECNINISTTNYPCKVSTGRHPISMVALSPLGALVACYKGVSCSIGSNRVGIIKQLNKGCSYITNQDADTVTIDNTVYQLSKVEGEQHVIKGRPVSSSFDPVKFPEDQFNVALDQVFESIENSQALVDQSNRILSSAEKGNTGSGGSGSGEKAAKAEEAARKMEELFKKHKIVAVLRANSVEEAIEKAVAVFAGGVHLIEITFTVPDADTVIKALSVLKEKGAIIGAGTVTSVEQCRKAVESGAEFIVSPHLDEEISQFCKEKGVFYMPGVMTPTELVKAMKLGHTILKLFPGEVVGPQFVKAMKGPFPNVKFVPTGGVNLDNVCEWFKAGVLAVGVGSALVKGTPDEVREKAKAFVEKIRGCTE

Second Assemblies

The nanostructures of the invention may comprise multiple copies of atrimeric first assembly and multiple copies of a second assembly. Thesecond assembly comprises a protein-protein interface that inducesmultiple copies of the second polypeptide to self-associate to form thesecond assemblies. Multiple oligomeric states of the second assembly maybe compatible with nanostructure formation, including dimeric (twocopies), trimeric (three copies), tetrameric (four copies), pentameric(five copies), hexameric (six copies), or higher oligomeric states. Eachcopy of the second assembly further comprises a surface-exposedinterface that interacts with a complementary surface-exposed interfaceon a trimeric assembly domain. As described in King et al., Bale et al.,and patent publications WO2014124301 A1 and US20160122392 A1, thecomplementary interface between the trimeric assembly domain and secondassembly domain drives the assembly of multiple copies of the trimericassembly domain and second assembly domain to a target nanostructure. Invarious specific embodiments:

(a) when each first polypeptide is DS-Cav1-foldon-T33-31A (SEQ ID NO:69)or DS-Cav1-T33-31A (SEQ ID NO:70), each second polypeptide is T33-31B(SEQ ID NO:44);

(b) when each first polypeptide is DS-Cav1-foldon-T33-15B (SEQ ID NO:71)or DS-Cav1-T33-15B (SEQ ID NO:72), each second polypeptide is T33-15A(SEQ ID NO:45);

(c) when each first polypeptide is DS-Cav1-foldon-I53-50A (SEQ ID NO:73)or DS-Cav1-I53-50A (SEQ ID NO:74), each second polypeptide is I53-50B(SEQ ID NO:8), I53-50B.1 (SEQ ID NO:32), I53-50B.1NegT2 (SEQ ID NO:33),or 153-50B.4PosT1 (SEQ ID NO:34);

(d) when each first polypeptide is DS-Cav1-I32-28A (SEQ ID NO:75), eachsecond polypeptide is I32-28B.

Assembly of Full Valency Nanostructures by In Vitro Assembly of TwoComponents

In some embodiments, each trimeric first assembly of the nanostructurebears an identical F protein as a genetic fusion; these nanostructuresdisplay the F protein at full (100%) valency. Such nanostructures areproduced from purified first polypeptides and second polypeptides in aprocess called in vitro assembly. Purified trimeric first polypeptidescomprising an F protein, are mixed with appropriate second polypeptidesin an approximately 1:1 molar ratio in aqueous conditions (see FIG. 1).The second assembly interacts with the trimeric first assembly in orderto drive assembly of the target nanostructure. Successful assembly ofthe target nanostructure can be confirmed by analyzing the in vitroassembly reaction by common biochemical or biophysical methods used toassess the physical size of proteins or protein assemblies, includingbut not limited to size exclusion chromatography, native(non-denaturing) gel electrophoresis, dynamic light scattering,multi-angle light scattering, analytical ultracentrifugation, negativestain electron microscopy, cryo-electron microscopy, or X-raycrystallography. If necessary, the assembled nanostructure can bepurified from other species or molecules present in the in vitroassembly reaction using preparative techniques commonly used to isolateproteins by their physical size, including but not limited to sizeexclusion chromatography, preparative ultracentrifugation, tangentialflow filtration, or preparative gel electrophoresis. The presence of theF protein in the nanostructure can be assessed by techniques commonlyused to determine the identity of protein molecules in aqueoussolutions, including but not limited to SDS-PAGE, mass spectrometry,protein sequencing, or amino acid analysis. The accessibility of the Fprotein on the exterior of the particle, as well as its conformation orantigenicity, can be assessed by techniques commonly used to detect thepresence and conformation of an antigen, including but not limited tobinding by monoclonal antibodies, conformation-specific monoclonalantibodies, or anti-sera specific to the antigen.

In Vitro Assembly of Partial Valency Nanostructures

In other embodiments, the nanostructures of the invention comprise oneor more copies of trimeric first assemblies bearing F proteins asgenetic fusions as well as one or more trimeric first assemblies that donot bear F proteins as genetic fusions; these nanostructures display theF proteins at partial valency. These partial valency nanostructures areproduced by performing in vitro assembly with mixtures of firstpolypeptides in which the fraction of trimeric first assemblies bearingan F protein as a genetic fusion is equal to the desired valency of theantigen in the resulting nanostructure. The in vitro assembly reactiontypically contains an approximately 1:1 molar ratio of total firstpolypeptides to total second polypeptides. By way of non-limitingexample, performing an in vitro assembly reaction with a mixture oftrimeric assemblies in which one half of the first polypeptides bear anF protein as a genetic fusion would yield an assembled nanostructurewith an F protein valency of 50%. That is, 50% of the possible sites forF protein display on the nanostructure would be occupied. By way ofnon-limiting example, if the nanostructure is a 120-subunit assemblywith icosahedral symmetry, the nanostructure comprises 20 total trimericbuilding blocks, and a 50% valency nanostructure displays 10 of thepossible 20 F protein trimers. In this way, the ratio of Fprotein-bearing first polypeptides to first polypeptides lacking Fproteins in an in vitro assembly reaction can be used to precisely tunethe F protein valency of the resulting nanostructures. It will beunderstood by those of skill in the art that it is the average valencythat can be tuned in this manner; the valency of individualnanostructures in the mixture will be a distribution centered around theaverage. Successful assembly of such partial valency nanostructures canbe assessed using the techniques described above for evaluatingfull-valency nanostructures, and, if necessary, the partial valencynanostructures can be purified using the methods described for purifyingfull-valency nanostructures. The average valency of F protein-bearingfirst polypeptides in a given sample can be assessed by quantitativeanalysis using the techniques described above for evaluating thepresence of F proteins in full-valency nanostructures.

In Vitro Assembly of Nanostructures Co-Displaying Multiple F Proteins

In other embodiments, the nanostructures of the invention comprise twoor more distinct first polypeptides bearing different F proteins asgenetic fusions; these nanostructures co-display multiple different Fproteins on the same nanostructure. These multi-antigen nanostructuresare produced by performing in vitro assembly with mixtures of firstpolypeptides in which each first polypeptide bears one of two or moredistinct F proteins as a genetic fusion. The fraction of each firstpolypeptide in the mixture determines the average valency of each Fprotein in the resulting nanostructures. The in vitro assembly reactiontypically contains an approximately 1:1 molar ratio of total trimericfirst polypeptides to total second polypeptides. The presence andaverage valency of each F protein-bearing first polypeptides in a givensample can be assessed by quantitative analysis using the techniquesdescribed above for evaluating the presence of F proteins infull-valency nanostructures.

In various embodiments, the nanostructures are between about 20nanometers (nm) to about 40 nm in diameter, with interior lumens betweenabout 15 nm to about 32 nm across and pore sizes in the protein shellsbetween about 1 nm to about 14 nm in their longest dimensions.

In one embodiment, the nanostructure has icosahedral symmetry. In thisembodiment, the nanostructure may comprise 60 copies of the firstpolypeptide and 60 copies of the second polypeptide. In one suchembodiment, the number of identical first polypeptides in each firstassembly is different than the number of identical second polypeptidesin each second assembly. For example, in one embodiment, thenanostructure comprises twelve first assemblies and twenty secondassemblies; in this embodiment, each first assembly may, for example,comprise five copies of the identical first polypeptide, and each secondassembly may, for example, comprise three copies of the identical secondpolypeptide. In another embodiment, the nanostructure comprises twelvefirst assemblies and thirty second assemblies; in this embodiment, eachfirst assembly may, for example, comprise five copies of the identicalfirst polypeptide, and each second assembly may, for example, comprisetwo copies of the identical second polypeptide. In a further embodiment,the nanostructure comprises twenty first assemblies and thirty secondassemblies; in this embodiment, each first assembly may, for example,comprise three copies of the identical first polypeptide, and eachsecond assembly may, for example, comprise two copies of the identicalsecond polypeptide. All of these embodiments are capable of formingsynthetic nanomaterials with regular icosahedral symmetry. In variousfurther embodiments, oligomeric states of the first and secondpolypeptides are as follows:

I53-34A: trimer+I53-34B: pentamer;

I53-40A: pentamer+I53-40B: trimer;

I53-47A: trimer+I53-47B: pentamer;

I53-50A: trimer+I53-50B: pentamer;

153-51A: trimer+153-51B: pentamer;

I32-06A: dimer+I32-06B: trimer;

I32-19A: trimer+I32-19B: dimer;

I32-28A: trimer+I32-28B: dimer;

I52-03A: pentamer+I52-03B: dimer;

I52-32A: dimer+I52-32B: pentamer; and

I52-33A: pentamer+I52-33B: dimer

In another embodiment, the nanostructure of any embodiment orcombination of embodiments of the invention has one or more of thefollowing characteristics, each as demonstrated in the examples thatfollow:

(a) binds prefusion F-specific antibodies including but not limited tomonoclonal antibody D25;

(b) forms a symmetrical structure, including but not limited to anicosahedral structure;

(c) is stable at 50° C.; and/or

(d) is stable in 2.25M guanidine hydrochloride.

In another aspect, the present invention provides isolated nucleic acidsencoding a fusion protein of the present invention. The isolated nucleicacid sequence may comprise RNA or DNA. As used herein, “isolated nucleicacids” are those that have been removed from their normal surroundingnucleic acid sequences in the genome or in cDNA sequences. Such isolatednucleic acid sequences may comprise additional sequences useful forpromoting expression and/or purification of the encoded protein,including but not limited to polyA sequences, modified Kozak sequences,and sequences encoding epitope tags, export signals, and secretorysignals, nuclear localization signals, and plasma membrane localizationsignals. It will be apparent to those of skill in the art, based on theteachings herein, what nucleic acid sequences will encode the proteinsof the invention.

In a further aspect, the present invention provides recombinantexpression vectors comprising the isolated nucleic acid of anyembodiment or combination of embodiments of the invention operativelylinked to a suitable control sequence. “Recombinant expression vector”includes vectors that operatively link a nucleic acid coding region orgene to any control sequences capable of effecting expression of thegene product. “Control sequences” operably linked to the nucleic acidsequences of the invention are nucleic acid sequences capable ofeffecting the expression of the nucleic acid molecules. The controlsequences need not be contiguous with the nucleic acid sequences, solong as they function to direct the expression thereof. Thus, forexample, intervening untranslated yet transcribed sequences can bepresent between a promoter sequence and the nucleic acid sequences andthe promoter sequence can still be considered “operably linked” to thecoding sequence. Other such control sequences include, but are notlimited to, polyadenylation signals, termination signals, and ribosomebinding sites. Such expression vectors can be of any type known in theart, including but not limited to plasmid and viral-based expressionvectors. The control sequence used to drive expression of the disclosednucleic acid sequences in a mammalian system may be constitutive (drivenby any of a variety of promoters, including but not limited to, CMV,SV40, RSV, actin, EF) or inducible (driven by any of a number ofinducible promoters including, but not limited to, tetracycline,ecdysone, steroid-responsive). The construction of expression vectorsfor use in transfecting prokaryotic cells is also well known in the art,and thus can be accomplished via standard techniques. (See, for example,Sambrook, Fritsch, and Maniatis, in: Molecular Cloning, A LaboratoryManual, Cold Spring Harbor Laboratory Press, 1989; Gene Transfer andExpression Protocols, pp. 109-128, ed. E. J. Murray, The Humana PressInc., Clifton, N.J.), and the Ambion 1998 Catalog (Ambion, Austin,Tex.). The expression vector must be replicable in the host organismseither as an episome or by integration into host chromosomal DNA. In apreferred embodiment, the expression vector comprises a plasmid.However, the invention is intended to include other expression vectorsthat serve equivalent functions, such as viral vectors.

In another aspect, the present invention provides host cells that havebeen transfected with the recombinant expression vectors disclosedherein, wherein the host cells can be either prokaryotic or eukaryotic,such as mammalian cells. The cells can be transiently or stablytransfected. Such transfection of expression vectors into prokaryoticand eukaryotic cells can be accomplished via any technique known in theart, including but not limited to standard bacterial transformations,calcium phosphate co-precipitation, electroporation, or liposomemediated-, DEAE dextran mediated-, polycationic mediated- or viralmediated transfection. (See, for example, Molecular Cloning: ALaboratory Manual (Sambrook, et al., 1989, Cold Spring Harbor LaboratoryPress; Culture of Animal Cells: A Manual of Basic Technique, 2nd Ed. (R.I. Freshney. 1987. Liss, Inc. New York, N.Y.). A method of producing apolypeptide according to the invention is an additional part of theinvention. The method comprises the steps of (a) culturing a hostaccording to this aspect of the invention under conditions conducive tothe expression of the polypeptide, and (b) optionally, recovering theexpressed polypeptide.

In a further aspect, the invention provides an immunogenic compositioncomprising an effective amount of the nanostructure of any embodiment orcombination of embodiments of the invention and a pharmaceuticallyacceptable carrier. The composition may comprise (a) a lyoprotectant;(b) a surfactant; (c) a bulking agent; (d) a tonicity adjusting agent;(e) a stabilizer; (f) a preservative and/or (g) a buffer.

In some embodiments, the buffer in the pharmaceutical composition is aTris buffer, a histidine buffer, a phosphate buffer, a citrate buffer oran acetate buffer. The composition may also include a lyoprotectant,e.g. sucrose, sorbitol or trehalose. In certain embodiments, thecomposition includes a preservative e.g. benzalkonium chloride,benzethonium, chlorohexidine, phenol, m-cresol, benzyl alcohol,methylparaben, propylparaben, chlorobutanol, o-cresol, p-cresol,chlorocresol, phenylmercuric nitrate, thimerosal, benzoic acid, andvarious mixtures thereof. In other embodiments, the composition includesa bulking agent, like glycine. In yet other embodiments, the compositionincludes a surfactant e.g., polysorbate-20, polysorbate-40,polysorbate-60, polysorbate-65, polysorbate-80 polysorbate-85,poloxamer-188, sorbitan monolaurate, sorbitan monopalmitate, sorbitanmonostearate, sorbitan monooleate, sorbitan trilaurate, sorbitantristearate, sorbitan trioleaste, or a combination thereof. Thecomposition may also include a tonicity adjusting agent, e.g., acompound that renders the formulation substantially isotonic orisoosmotic with human blood. Exemplary tonicity adjusting agents includesucrose, sorbitol, glycine, methionine, mannitol, dextrose, inositol,sodium chloride, arginine and arginine hydrochloride. In otherembodiments, the composition additionally includes a stabilizer, e.g., amolecule which substantially prevents or reduces chemical and/orphysical instability of the nanostructure, in lyophilized or liquidform. Exemplary stabilizers include sucrose, sorbitol, glycine,inositol, sodium chloride, methionine, arginine, and argininehydrochloride.

The nanostructure may be the sole active agent in the composition, orthe composition may further comprise one or more other agents suitablefor an intended use, including but not limited to adjuvants to stimulatethe immune system generally and improve immune responses overall. Anysuitable adjuvant can be used. The term “adjuvant” refers to a compoundor mixture that enhances the immune response to an antigen. Exemplaryadjuvants include, but are not limited to, Adju-Phos™, Adjumer™,albumin-heparin microparticles, Algal Glucan, Algammulin, Alum, AntigenFormulation, AS-2 adjuvant, autologous dendritic cells, autologous PBMC,Avridine™, B7-2, BAK, BAY R1005, Bupivacaine, Bupivacaine-HCl, BWZL,Calcitriol, Calcium Phosphate Gel, CCR5 peptides, CFA, Cholera holotoxin(CT) and Cholera toxin B subunit (CTB), Cholera toxin A1-subunit-ProteinA D-fragment fusion protein, CpG, CRL1005, Cytokine-containingLiposomes, D-Murapalmitine, DDA, DHEA, Diphtheria toxoid, DL-PGL, DMPC,DMPG, DOC/Alum Complex, Fowlpox, Freund's Complete Adjuvant, GammaInulin, Gerbu Adjuvant, GM-CSF, GMDP, hGM-CSF, hIL-12 (N222L),hTNF-alpha, IFA, IFN-gamma in pcDNA3, IL-12 DNA, IL-12 plasmid,IL-12/GMCSF plasmid (Sykes), IL-2 in pcDNA3, IL-2/Ig plasmid, IL-2/Igprotein, IL-4, IL-4 in pcDNA3, Imiquimod™, ImmTher™, ImmunoliposomesContaining Antibodies to Costimulatory Molecules, Interferon-gamma,Interleukin-1 beta, Interleukin-12, Interleukin-2, Interleukin-7,ISCOM(s)™, Iscoprep 7.0.3™, Keyhole Limpet Hemocyanin, Lipid-basedAdjuvant, Liposomes, Loxoribine, LT(R192G), LT-OA or LT Oral Adjuvant,LT-R192G, LTK63, LTK72, MF59, MONTANIDE ISA 51, MONTANIDE ISA 720, MPL™,MPL-SE, MTP-PE, MTP-PE Liposomes, Murametide, Murapalmitine, NAGO, nCTnative Cholera Toxin, Non-Ionic Surfactant Vesicles, non-toxic mutantE112K of Cholera Toxin mCT-E12K, p-Hydroxybenzoique acid methyl ester,pCIL-10, pCIL12, pCMVmCAT, pCMVN, Peptomer-NP, Pleuran, PLG, PLGA, PGA,and PLA, Pluronic L121, PMMA, PODDS™, Poly rA: Poly rU, Polysorbate 80,Protein Cochleates, QS-21, Quadri A saponin, Quil-A, Rehydragel HPA,Rehydragel LV, RIBI, Ribilike adjuvant system (MPL, TMD, CWS), S-28463,SAF-1, Sclavo peptide, Sendai Proteoliposomes, Sendai-containing LipidMatrices, Span 85, Specol, Squalane 1, Squalene 2, Stearyl Tyrosine,Tetanus toxoid (TT), Theramide™, Threonyl muramyl dipeptide (TMDP), TyParticles, and Walter Reed Liposomes. Selection of an adjuvant dependson the subject to be treated. Preferably, a pharmaceutically acceptableadjuvant is used.

In another aspect, the invention provides methods for generating animmune response to paramyxovirus and/or pneumovirus F protein in asubject, comprising administering to the subject an effective amount ofthe immunogenic composition of any embodiment or combination ofembodiments of the invention to generate the immune response. In afurther aspect, the invention provides methods for treating orpreventing a paramyxovirus and/or pneumovirus infection in a subject,comprising administering to the subject an effective amount of theimmunogenic composition of any embodiment or combination of embodimentsof the invention, thereby treating or preventing paramyxovirus and/orpneumovirus infection in the subject.

In one embodiment, the paramyxovirus and/or pneumovirus comprisesrespiratory syncytial virus. “Respiratory Syncytial Virus” and “RSV”refer to a negative-sense, single-stranded RNA virus that causes arespiratory disease, especially in children. When the method comprisestreating an RSV infection, the immunogenic compositions are administeredto a subject that has already been infected with the RSV, and/or who issuffering from symptoms (including but not limited to lower respiratorytract infections, upper respiratory tract infections, bronchiolitis,pneumonia, fever, listlessness, diminished appetite, recurrent wheezing,and asthma) indicating that the subject is likely to have been infectedwith the RSV. As used herein, “treat” or “treating” includes, but is notlimited to accomplishing one or more of the following: (a) reducingparamyxovirus and/or pneumovirus titer in the subject; (b) limiting anyincrease of paramyxovirus and/or pneumovirus titer in the subject; (c)reducing the severity of paramyxovirus and/or pneumovirus symptoms; (d)limiting or preventing development of paramyxovirus and/or pneumovirussymptoms after infection; (e) inhibiting worsening of paramyxovirusand/or pneumovirus symptoms; (f) limiting or preventing recurrence ofparamyxovirus and/or pneumovirus symptoms in subjects that werepreviously symptomatic for paramyxovirus and/or pneumovirus infection;and/or promoting maternal transmission of paramyxovirus and/orpneumovirus antibodies to infants (after maternal immunization).

When the method comprises limiting a paramyxovirus and/or pneumovirusinfection, the immunogenic compositions are administeredprophylactically to a subject that is not known to be infected, but maybe at risk of exposure to the paramyxovirus and/or pneumovirus. As usedherein, “limiting” means to limit RSV infection in subjects at risk ofRSV infection. Groups at particularly high risk include children underage 18 (particularly infants 3 years or younger), adults over the age of65, and individuals suffering from any type of immunodeficiency.

As used herein, an “effective amount” refers to an amount of theimmunogenic composition that is effective for treating and/or limitingRSV infection. The immunogenic compositions are typically formulated asa pharmaceutical composition, such as those disclosed above, and can beadministered via any suitable route, including orally, parentally, byinhalation spray, rectally, or topically in dosage unit formulationscontaining conventional pharmaceutically acceptable carriers, adjuvants,and vehicles. The term parenteral as used herein includes, subcutaneous,intravenous, intra-arterial, intramuscular, intrasternal,intratendinous, intraspinal, intracranial, intrathoracic, infusiontechniques or intraperitoneally. Polypeptide compositions may also beadministered via microspheres, liposomes, immune-stimulating complexes(ISCOMs), or other microparticulate delivery systems or sustainedrelease formulations introduced into suitable tissues (such as blood).Dosage regimens can be adjusted to provide the optimum desired response(e.g., a therapeutic or prophylactic response). A suitable dosage rangemay, for instance, be 0.1 ug/kg-100 mg/kg body weight of the F proteinor antigenic fragment thereof. The composition can be delivered in asingle bolus, or may be administered more than once (e.g., 2, 3, 4, 5,or more times) as determined by attending medical personnel.

In one embodiment, the administering results in production ofparamyxovirus and/or pneumovirus neutralizing antibodies in the subject.In another embodiment, the neutralizing antibodies are present in seraof the subject at a titer (1/ID₅₀) of at least 1,000; in otherembodiments, the neutralizing antibodies are present in sera of thesubject at a titer of 2,000 or 5,000.

EXAMPLES Methods: Expression and Screening of Trimeric Building BlocksComprising an F Protein and a Trimeric Assembly Domain

Human codon-optimized sequences for trimeric building blocks includingand lacking DS-Cav1 fusions were ordered from Genscript. Building blocksfor single-component nanostructures (i.e., I3-01) were cloned into thepcDNA3.1 vector (ThermoFisher Scientific) containing one CMV promoter,while building blocks for two-component nanostructures (e.g., I53-50)were cloned into the pBudCE4.™ vector (ThermoFisher Scientific)containing both CMV and EF-1α promoters. Recombinant proteins wereexpressed by transient transfection of Expi293F™ cells (ThermoFisherScientific) using polyethylenimine (PEI). Cell cultures were harvestedfive days post-transfection by centrifugation. Secreted proteins wereanalyzed by ELISA, using either direct coating of the cell supernatantsor by sandwich ELISA. Briefly, 96-well MaxiSorp™ plates (Nunc) werecoated with cell supernatant for direct ELISA or murine anti-His tagmonoclonal antibody (ThermoFisher Scientific) for sandwich ELISA.Secreted proteins were detected using the human Palivizumab, MPE8, RSD5,and D25 monoclonal antibodies. Transfected Expi293F cells were fixed andpermeabilized with BD cytofix/cytoperm (BD Biosciences), incubated withhuman Palivizumab, MPE8, and D25 monoclonal antibodies, and stained withAlexa Fluor 647-conjugated anti-human IgG antibody (JacksonImmunoResearch). Stained cells were counted with a FACS Fortessarv flowcytometer (BD Biosciences). Analysis was performed with FlowJoPsoftware. Cell lines were routinely tested for mycoplasma contamination.

Expression and Purification of DS-Cav1-I53-50A

Lentivirus was produced by transient transfection of 293T (ATCC) cellsusing linear 25-kDa polyethyleneimine (PEI; Polysciences). Briefly,4×10⁶ cells were plated onto 10 cm tissue culture plates. After 24 h, 3μg of psPAX2, 1.5 μg of pMD2G (Addgene™ plasmid #12260 and #12259,respectively) and 6 μg of lentiviral vector plasmid were mixed in 500 μldiluent (5 mM HEPES, 150 mM NaCl, pH=7.05) and 42 μl of PEI (1 mg/ml)and incubated for 15 min. The DNA/PEI complex was then added to theplate drop-wise. Lentivirus was harvested 48 h post-transfection andconcentrated 100-fold by low-speed centrifugation at 8000 g for 18 h.Transduction of the target cell line was carried out in 125 mL shakeflasks containing 10×10⁶ cells in 10 mL of growth media. 100 uL of 100×lentivirus was added to the flask and the cells were incubated withshaking (225 rpm) at 37° C., in 8% CO₂ for 4-6 h. 20 mL of growth mediawas added to the shake flask after 4-6 h.

Transduced cells were expanded every other day to a density of 1×10⁶cells/ml until a final culture size of 4 L was reached. The media washarvested after 17 days of total incubation after measuring final cellconcentration (˜5×10⁶ cells/mL) and viability (˜90% viable). Culturesupernatant was harvested by low-speed centrifugation to remove cellsfrom the supernatant. NaCl and NaN₃ were added to final concentrationsof 250 mM and 0.02%, respectively. The supernatant was loaded over one 5mL HisTrap™ FF Crude column (GE Healthsciences) at 5 ml/min by an AKTAPure™ (GE Healthsciences). The nickel elution was applied to a HiLoad™16/600 Superdex 200 μg column (GE Healthsciences) to further purify thetarget protein by size-exclusion chromatography. The size-exclusionpurified target protein was snap frozen in liquid nitrogen and stored at−80° C.

In Vitro Assembly of DS-Cav1-Bearing Nanostructures

100% valency particles (20 DS-Cav1 trimers per icosahedralnanostructure) were prepared by mixing DS-Cav1-foldon-I53-50A trimersand I53-50B.4PT1 pentamers at 5 μM each and incubating with rockingovernight at 4° C. In some cases, assembled nanostructures were purifiedfrom excess components remaining in the in vitro assembly reaction usinga GE Sephacryl S-500 HR 16/60 column in a buffer comprising 25 mM TrispH 8, 250 mM NaCl, 5% glycerol. Sample load and SEC fractions wereanalyzed by SDS-PAGE in the presence and absence of reducing agent. Peakfractions were pooled, concentrated using a GE Vivaspin™ 20 30 kDa MWCOcentrifugal filter, and quantified using an Agilent 8454spectrophotometer.

66% valency particles (14 DS-Cav1 trimers per icosahedral nanostructure)were prepared by mixing DS-Cav1-foldon-I53-50A trimers, I53-50A trimers,and 153-50B.4PosT1 pentamers at 50, 25, and 75 μM, respectively. 33%valency particles (7 DS-Cav1 trimers per icosahedral nanostructure) wereprepared by mixing DS-Cav1-foldon-I53-50A trimers, 153-50A trimers, and153-50B.4PosT1 pentamers at 25, 50, and 75 μM, respectively. The invitro assembly reactions were allowed to incubate with rocking overnightat 4° C. In some cases, assembled nanostructures were purified fromexcess components remaining in the in vitro assembly reaction using a GESephacryl™ S-500 HR 16/60 column in a buffer comprising 25 mM Tris pH 8,250 mM NaCl, 5% glycerol. Sample load and SEC fractions were analyzed bySDS-PAGE in the presence and absence of reducing agent. Peak fractionswere pooled, concentrated using a GE Vivaspin™ 20 30 kDa MWCOcentrifugal filter, and quantified using an Agilent 8454spectrophotometer after centrifuging at 21,000 g for 10 minutes at 4° C.Samples were then transferred to cryogenic tubes in 1 mL aliquots at 1.1mg/mL for the 33% valency particles and 0.6 mg/mL for the 66% valencyparticles, flash frozen in liquid nitrogen, and stored at −80° C.

Electron Microscopy of DS-Cav1-Bearing Nanostructures

Samples were prepared for negative stain EM by diluting to 0.01 mg/mLusing 25 mM Tris pH 8, 250 mM NaCl, 5% glycerol and 3.5 L was incubatedon a glow-discharged, copper, carbon-coated grid for 20 seconds beforeblotting away the liquid with a piece of Whatman No. 1 filter paper.Within seconds of blotting away the sample, a 3.5 L droplet of stain (2%w/v uranyl formate) was deposited and blotted away immediately, and thena second cycle of staining/blotting was performed.

Circular Dichroism (CD) Spectropolarimetry

CD spectra from F proteins (0.5 mg ml⁻¹) were recorded on a Chirascan™spectropolarimeter (Applied Photophysics) over the wavelength range of195 to 260 nm at a bandwidth of 1 nm, step size of 0.5 nm, and 1 s perstep. The spectra in the far-ultraviolet region required an average ofthree scans and were subtracted from blank spectra performed withbuffer. Thermal denaturation was monitored by performing scans atintervals of 1° C., after equilibration for 1 min at each temperature.Data were fitted to a simple first order curve. The values of AA222 arerepresented on the y axis as the percentage of the values recorded at20° C.

Enzyme-Linked Immunosorbent Assay (ELISA)

To test specific binding of antibody or sera, 96-well MaxiSorp™ plates(Nunc) were coated with serial dilutions of tissue culture supernatantsfrom cells expressing trimeric building blocks comprising F proteins anda trimeric assembly domain or 2 μg ml⁻¹ of the following purifiedproteins: Ds-Cav1 with foldon, Ds-Cav1 fused to atrimeric firstpolypeptide or DS-Cav1-displaying nanostructures. Plates were blockedwith 1% bovine serum albumin (BSA) and incubated with titratedantibodies (D25, MPE8, Palivizumab, RSD5) or murine sera followed byAP-conjugated goat anti-human IgG (Southern Biotech, 2040-04) or goatanti-mouse IgG (Southern Biotech, 1030-04). Plates were then washed withPBS buffer (Gibco, Invitrogen), 0.05% Tween-20 and substrate (p-NPP,Sigma) was added and plates were read at 405 nm.

Surface Plasmon Resonance (SPR)

The experiments were carried out at 25° C. on a ProteON™ XPR-36instrument (Bio-Rad Laboratories) in a PBS buffer (Gibco, Invitrogen),0.05% Tween-20. The D25 mAb was immobilized on a GLM sensor chip surfacethrough amine coupling at 1000 response units (RU) and a blank surfacewith no protein was created under identical coupling conditions for useas a reference. Monoclonal antibodies (D25, MPE8, Palivizumab and131-2a) were injected at a flow rate of 100 μl/min, at concentrations of50 nM in different sensor channels. The data were processed usingProteon software and double referenced by subtraction of the blanksurface and buffer only injection before local fitting of the data.

Vaccination and Serological Analysis

Female BALB/c mice 6-9 weeks of age were obtained from ENVIGOLaboratories (Italy). All proteins were formulated with AddaVax™adjuvant (Invivogen) according to the manufacturer's instruction. Micewere immunized subcutaneously (s.c) with a total protein dosecorresponding to 5 g of the DS-Cav1 antigen equivalent on day 0, 14, and28 in 50% AddaVax™ in PBS. Mice were bled on day 24 and 40. Recoveredsera were used to measure binding and neutralizing titers. Bindingtiters were measured by coating 3 g/ml of DS-Cav1, I53-50 nanostructuresor I53-50 nanostructure subunits.

Virus Neutralization Assay and Microscopy Analysis

Neutralization of RSV infection by sera was measured using amicro-neutralization flow cytometry-based assay. Serial dilutions ofsera were pre-incubated with RSV for 1 hour at 37° C. and added to 10000HEp-2 (ATCC® CCL-23™) cells/well in 96-well flat-bottom plates (MOI of1). After 24 hours, cells were washed, detached and fixed with 2%formaldehyde. Percentage of GFP positive cells were measured by Highthroughput FACS with an Intellicyt coupled to an automated platform. TheTissue Culture Inhibiting Dilution (TCID) neutralizing 50% of theInfection (TCID₅₀) was calculated by nonlinear regression with Prism 7(GraphPad Software).

Non-Human Primate (NHP) Immunization

Rhesus macaques were immunized i.m. (right quadriceps) at weeks 0 and 4with trimeric DS-Cav1 (50 μg; n=4) or DS-Cav1-foldon-I53-50nanostructures (96 μg, comprising 50 μg of displayed DS-Cav1; n=5)formulated in the MF59-like adjuvant SWE. Sera were obtained at weeks 6and 16 for serological analysis.

Stability of DS-Cav1-Bearing Nanostructures by Relative Binding to D25

Experiments were carried out at 20° C. on a ProteON™ XPR-36 instrument(Bio-Rad Laboratories) in a PBS buffer (Gibco, Thermo Fisher Scientific)and 0.05% Tween-(Sigma). 100 nM D25 antibody was immobilized on a GLMsensor chip surface through amine coupling (EDC/NHS chemistry) and ablank surface with no antibody was created under identical couplingconditions for use as a reference. Analyte proteins (soluble DS-Cav1,soluble DS-Cav1-I53-50A and DS-Cav1-foldon-I53-50 nanostructures), heatstressed at different temperatures (20, 50, 70 or 80° C.) for 1 h, wereinjected at a flow rate of 100 μl/min, at a concentration of 50 nM inthe different sensor channels. Data were processed using Proteonsoftware and double referenced by subtraction of the blank surface andbuffer-only injection before local fitting of the data.

Chemical Denaturation of Nanostructure-Related Proteins

Trimeric DS-Cav1, DS-Cav1-I53-50A, DS-Cav1-I53-50, I53-50, trimericI53-50A, or pentameric 153-50B4PT1 was diluted to a final concentrationof 2.5 μM in 25 mM Tris pH 8, 250 mM NaCl, 5% glycerol with varyingconcentrations of guanidine hydrochloride, ranging from 0 M to 6.5 M,increasing in 0.25 M increments. Samples were prepared in triplicate andincubated for 16 hours at ambient temperature. On a Cary EclipseFluorescence Spectrophotometer, intrinsic fluorescence was measured foreach guanidine hydrochloride concentration of each protein and of eachreplicate. A Peltier controller was used in the cell holder to maintaina temperature of 25° C. throughout all experiments. Using a 10 mm cell(Agilent Cuvette, part #6610021600), fluorescence spectra werecollected, exciting at 290 nm and scanning emission from 310 nm to 510nm at a rate of 60 nm/minute with a bandpass of 1 nm.

Statistical Analysis

No statistical methods were used to predetermine sample size. Data wereanalyzed with Prism 6 (GraphPad™ Software) using the two-tailednon-parametric Mann-Whitney U test for two groups' comparison, orKruskall-Wallis test (and Dunn's posttest) when three or more groupswere compared.

Results Trimeric Building Blocks Comprising an F Protein and a TrimericAssembly Domain

Several trimeric building blocks, each comprising an F proteingenetically fused to a trimeric assembly domain, were found to besecreted from HEK293F cells with their F proteins in a well-folded,prefusion conformation as judged by prefusion-specific monoclonalantibody binding in ELISA assays. FIG. 2 shows an example of ELISA dataanalyzing the supernatant of HEK293F cells expressing DS-Cav1-foldon,DS-Cav1-foldon-T33-31A, and DS-Cav1-T33-31A. Several other trimericbuilding blocks yielded detectable secretion of well-folded, prefusion Fproteins.

Expression and Purification of DS-Cav1-Foldon-I53-50A

A lentiviral vector encoding DS-Cav1-foldon-I53-50A was used totransduce HEK293F cells for large-scale expression. The secreted proteinwas purified from tissue culture supernatants by immobilized metalaffinity chromatography and size exclusion chromatography. Sizeexclusion chromatograms (FIG. 3) indicated that the purified proteinformed a single, monodisperse species.

Expression and Purification of I53-50B.4PT

I53-50B.4PT1, a pentameric protein comprising a second assembly domainthat interacts with the trimeric assembly domain in I53-50A orDS-Cav1-foldon-I53-50A to drive assembly of icosahedral I53-50-basednanostructures, was expressed and purified as described in Bale et al.and patent publication US20160122392 A1.

In Vitro Assembly and Characterization of DS-Cav1-Bearing I53-50Nanostructures

I53-50 is a 120-subunit two-component nanostructure with icosahedralsymmetry comprising 20 trimeric (I53-50A) and 12 pentameric (I53-50B)building blocks, as recently described by Bale et al. The N terminus ofI53-50A is exposed on the exterior of the 153-50 nanostructure, whichenables the display of antigens on the nanostructure exterior throughgenetic fusion to the I53-530A N terminus. PurifiedDS-Cav1-foldon-I53-50A and I53-50B.4PT1 were assembled in vitro to form120-subunit icosahedral nanostructures displaying various amounts ofDS-Cav1 on the nanostructure exteriors by mixing the two purifiedproteins in various molar ratios. In separate preparations,nanostructures displaying DS-Cav1 at valencies of 100% (20 trimers), 66%(14 trimers), and 33% (˜7 trimers) were prepared as described above. Thespecies present in the in vitro assembly reactions after overnightincubation were assessed by several techniques, including size exclusionchromatography-multi-angle light scattering (SEC-MALS), dynamic lightscattering, and UV/vis spectroscopy. Assembled, 120-subunitnanostructures were purified from the in vitro assembly reactions usingsize exclusion chromatography (an example chromatogram obtained usingthe 100% valency nanostructures is presented in FIG. 4). The purifiednanostructures were characterized by negative stain electron microscopy,which revealed fields of monodisperse particles in which DS-Cav1 wasclearly visible as spikes projecting outward from the core icosahedralI53-50 assembly (an example micrograph obtained using the 100% valencyparticles is presented in FIG. 5). ELISA assays using monoclonalantibodies specific to the prefusion conformation confirmed that theDS-Cav1 thus displayed on the nanostructure exteriors was well-foldedand antigenically intact (FIG. 6). Surface plasmon resonance experimentsevaluating the kinetics of monoclonal antibody binding revealed thatantibody dissociation from the 100% valency DS-Cav1-foldon-I53-50nanostructures was slower than from DS-Cav1-foldon trimers, likely dueto avidity effects deriving from the multivalent presentation of DS-Cav1on the nanostructure exterior (FIG. 6). Together, these experimentsconfirmed that the DS-Cav1-foldon-I53-50 nanostructures formedmonodisperse, icosahedral nanostructures that display well-folded,antigenically intact DS-Cav1 trimers on their exteriors. These findingsmotivated experiments to evaluate the utility of theDS-Cav1-foldon-I53-50 nanostructures as immunogens for inducing humoralimmune responses against DS-Cav1 in animals.

Immunogenicity of DS-Cav1-Foldon-I53-50 Nanostructures

The DS-Cav1-foldon-I53-50 nanostructures displaying DS-Cav1 at 33%, 66%,and 100% valency were injected into mice using a prime-boost strategy asdescribed above. Additional groups of mice were injected with trimericDS-Cav1-foldon as a benchmark for the humoral immune response inducedagainst DS-Cav1 by the nanostructures or I53-50 nanostructures lackingdisplayed DS-Cav1 as negative controls for a DS-Cav1 specific response.ELISA assays of serum extracted from the mice at defined time pointsafter the injections were used to measure DS-Cav1 specific antibodytiters present in the sera of the injected animals (FIG. 7). Asexpected, sera from animals injected with the 153-50 nanostructureslacking displayed DS-Cav1 did not contain antibodies specific toDS-Cav1. Trimeric DS-Cav1-foldon induced DS-Cav1-specific antibodies, inaccordance with previous results (McClellan et al.). The 33%, 66%, and100% valency DS-Cav1 nanostructures all induced higher DS-Cav-specificantibody titers than trimeric DS-Cav1-foldon, with the antibody titersincreasing with increasing DS-Cav1 valency. DS-Cav1-specific titers wereroughly 2.5-fold higher on average in mice injected with 100% valencyDS-Cav1-foldon-I53-50 nanostructures compared to DS-Cav1. These resultsdemonstrate that immunogens in which paramyxovirus F proteins aremultivalently displayed on self-assembling protein nanostructures caninduce higher humoral immune responses when injected into animals.

The sera from the mice injected with the series of immunogens describedabove was also evaluated for the presence of neutralizing antibodytiters using the standard neutralization assay in HEp-2 cells (FIG. 8).The trend in serum neutralizing antibody titers correlated highly withthe trend observed in DS-Cav-specific binding antibody titers. Sera fromanimals injected with the I53-50 nanostructures lacking displayedDS-Cav1 did not neutralize virus, consistent with the lack ofDS-Cav1-specific antibodies in these sera. The sera from animalsinjected with trimeric DS-Cav-1-foldon neutralized virus with an averagetiter (1/ID₅₀) of 3,030. The 33%, 66%, and 100% valency DS-Cav1-153-50nanostructures induced higher neutralizing antibody titers than trimericDS-Cav1-foldon, with average titers of 9,400, 20,000, and 30,500,respectively. These results demonstrate that the higher humoral responseinduced by immunogens in which paramyxovirus F proteins aremultivalently displayed on self-assembling protein nanostructures resultin more effective virus neutralization.

The DS-Cav1-foldon-I53-50 nanostructures were also injected into Rhesusmacaques to evaluate their immunogenicity in a primate immune system.The animals were injected intramuscularly at weeks 0 and 4 with eitherfree DS-Cav1 trimer or DS-Cav1-foldon-I53-50 nanostructures displayingDS-Cav1 at 100% valency. In both cases, the dose of DS-Cav1 antigen was50 μg, and the immunogens were formulated with the MF59-like,squalene-based oil-in-water emulsion adjuvant SWE. Sera obtained fromthe animals at weeks 6 and 16 were evaluated for anti-DS-Cav1 antibodytiters and RSV-neutralizing antibody titers (FIG. 9). The resultsmirrored those obtained in mice. At week 16, the mean anti-DS-Cav1antibody titer was 4-fold higher in animals injected with theDS-Cav1-foldon-I53-50 nanostructure compared to animals injected withtrimeric DS-Cav1. The mean RSV-neutralizing antibody titer at week 16was 16-fold higher in animals injected with the DS-Cav1-foldon-I53-50nanostructure compared to animals injected with trimeric DS-Cav1. Theseresults demonstrate, in a primate immune system, that immunogens inwhich paramyxovirus F proteins are multivalently displayed onself-assembling protein nanostructures induce more robust humoral immuneresponses, including high levels of virus-neutralizing antibodies, thanthe trimeric paramyxovirus F proteins alone.

Physical Stabilization of DS-Cav1 by Fusion to I53-50A

Given the key antigenic properties of prefusion F, we used twoorthogonal approaches to measure the physical stability of DS-Cav1 whenfused to 153-50A and/or when further assembled into the icosahedralnanostructure. The first assay measured the retention of binding by aprefusion-specific mAb (D25) after thermal stress, an approach that hasbeen used previously to characterize prefusion F stability (McLellan etal. 2013; Joyce et al. 2016; Krarup et al. 2015). Samples of trimericDS-Cav1, trimeric DS-Cav1-I53-50A, and DS-Cav1-I53-50 nanostructurescontaining equivalent concentrations (50 nM) of DS-Cav1 were split intofour aliquots and incubated at 20, 50, 70 or 80° C. for 1 hour. Aftercooling to room temperature, D25 binding was assayed by surface plasmonresonance (SPR). We found that all samples bound D25 equivalently at 20and 50° C., but lost most of their reactivity to D25 after 1 hour at 80°C. as previously reported for DS-Cav1 (McLellan et al. 2013; Joyce etal. 2016) (FIG. 10). Interestingly, while D25 was also unable to bindtrimeric DS-Cav1 incubated at 70° C. for 1 hour, trimericDS-Cav1-153-50A and the DS-Cav1-I53-50 nanostructures retained 50 and80% of their respective binding signals (FIG. 10). While the multivalentnature of the DS-Cav1-I53-50 nanostructures complicates directquantitative comparisons to trimeric DS-Cav1, these results indicatethat genetic fusion to the I53-50A trimer further stabilizes theprefusion conformation of DS-Cav1, and suggest that this increasedstability is maintained in the context of the assembled nanostructureimmunogen.

We used chemical denaturation in guanidine hydrochloride (GdnHCl),monitored by intrinsic tryptophan fluorescence, as a second,antibody-independent technique to evaluate physical stability. Analyzingfluorescence emission from DS-Cav1 incubated in 0-6.5 M GdnHCl revealedthat the protein undergoes two subtly distinct transitions, one between0.25 and 2.25 M GdnHCl and another between 2.25 and 5.75 M (FIG. 11). Incontrast, only a single transition is apparent for trimericDS-Cav1-I53-50A, occurring between 2.25 and 6.25 M GdnHCl (FIG. 11). Itis unclear at present whether the transition at lower [GdnHCl] observedfor DS-Cav1 is absent from trimeric DS-Cav1-I53-50A or simply shifted tohigher [GdnHCl]. However, it is clear that the native conformation ofDS-Cav1 is stabilized by genetic fusion to trimeric I53-50A, mirroringthe results obtained by measuring D25 binding after thermal stress.Comparing the data for the DS-Cav1-I53-50 nanostructure and the 153-50nanostructure alone (lacking fused DS-Cav1) indicated that thestabilization is maintained upon assembly to the icosahedralnanostructure (FIG. 11). The source of this effect is likely the extremestability of the 153-50A trimer. 153-50A is derived from the KDPGaldolase of the hyperthermophilic bacterium T. maritima and only beganto exhibit changes in fluorescence at very high (≥5.75 M) GdnHClconcentrations (FIG. 11).

We made addition constructs to assess the number of GS repeats and theneed for a stabilization domain such as the Foldon moiety.

Sequence Information

IPD Name MS (Da) Construct Information RSV_F-10 74005.38DS-Cav1-8GS-HelExt-50A RSV_F-11 74293.64 DS-Cav1-12GS-HelExt-50ARSV_F-12 74551.87 DS-Cav1-16GS-HelExt-50A RSV_F-13 77212.97DS-Cav1-foldon-10GS-HelExt-50A RSV_F-14 77558.28DS-Cav1-foldon-15GS-HelExt-50A RSV_F-15 77933.62DS-Cav1-foldon-20GS-HelExt-50A

Studies were based on expression yield in a small-scale transienttransfection. Plasmids capable of expressing the relevant constructswere transformed into NEB 5a E. coli cells and selected onLB+carbenicillin agar plates. 1 mL cultures were prepared by inoculatingTB media with a bacterial colony and again selecting with 50 ug/mLcarbenicillin. A Qiagen Mini Prep kit was used to purify plasmid fromthe E. coli cultures in accordance with their protocol. Expi293F™ Cells(ThermoFisher) were cultured in Expi293™ Expression Medium(ThermoFisher) supplemented with penicillin (100 u/mL) and streptomycin(100 μg/mL) at 8% CO₂, 37° C., and 125 rpm shaking.

On the day prior to transfection, cells were seeded at a concentrationof 2E6 cells/mL. On the day of transfection, cells were counted by aCountess II (ThermoFisher) with trypan blue to determine cell viability.Cell concentration was adjusted to 2.5E6 cells/mL, and cells whereplated into untreated 12-well plates (Corning) in 1 mL volumes. 1 μg ofDNA plasmid were transfected per each well using Expifectamine™(ThermoFisher), following the manufacturer's directions. Enhancers,components of ThermoFisher's Expifectamine™ Transfection Kit, were added18 hours after transfection. The 1 mL cultures were harvested 5 dayspost-transfection, and the cells were pelleted from the supernatant bycentrifugation at 1,500×g for 5 minutes at 4° C. Supernatants werefiltered through a 0.45 μM filter with a PVDF membrane.

Filtered supernatants containing DS-Cav1-I53-50A constructs weredenatured and boiled for 10 minutes at 95° C. for 10 minutes in 2×Laemmli buffer with 2-mercaptoethanol. SDS-PAGE separated the samplefractions, which were then transferred to a nitrocellulose membrane andprobed with palivizumab, followed with a secondary antibody, anti-humanconjugated to HRP. Blot was imaged using Clarity Western ECL BlottingSubstrate (Bio-Rad).

Filtered supernatants containing DS-Cav1-I53-50A constructs were boundto Nunc MaxiSorp™ 96-well plates in a two-fold dilution series. Thepre-fusion conformation-specific antibody D25 was used to detectDS-Cav1-I53-50A, followed by a secondary anti-human antibody conjugatedto HRP. Protein yield was determined colorimetrically via the substrateTMB and absorbances were collected at 450 nm.

The expression yields and binding of the prefusion-specific mAb D25(data not shown) indicate that all constructs express well and are inthe prefusion conformation. Those of skill in the art would haveexpected that a heterologous trimerization domain (such as the foldon)would be required for proper expression and folding of prefusion Fconstructs. Our results indicate that the 153-50A nanostructurecomponent can support the expression and proper folding of DS-Cav1without the use of a trimerization domain like the foldon. Binding ofD25 to these constructs suggests that they are antigenically intact andwould be expected to induce potent immune responses, includingneutralizing antibodies, similarly to nanostructures comprising theDS-Cav1-foldon-I53-50 fusion polypeptide.

1. A nanostructure, comprising: (a) a plurality of first assemblies,each first assembly comprising a plurality of identical firstpolypeptides; (b) a plurality of second assemblies, each second assemblycomprising a plurality of identical second polypeptides, wherein thesecond polypeptide differs from the first polypeptide; wherein theplurality of first assemblies non-covalently interact with the pluralityof second assemblies to form a nanostructure; and wherein thenanostructure displays multiple copies of one or more paramyxovirusand/or pneumovirus F proteins, or antigenic fragments thereof, on anexterior of the nanostructure.
 2. The nanostructure of claim 1, wherein:(a) the first polypeptides comprise polypeptides having at least 75%,80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%identity along their full length to the amino acid sequence of apolypeptide selected from the group consisting of SEQ ID NOS:1-51; and(b) the second polypeptides comprise polypeptides having at least 75%,80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%identity along their full length to the amino acid sequence of apolypeptide selected from the group consisting of SEQ ID NOS:1-51. 3.The nanostructure of claim 1, wherein the one or more paramyxovirusand/or pneumovirus F proteins, or antigenic fragments thereof, comprisea polypeptide having at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%,95%, 96%, 97%, 98%, 99%, or 100% identity along its full length to apolypeptide selected from the group consisting of SEQ ID NOS:53, 61-68,and
 101. 4. The nanostructure of claim 1, wherein the one or moreparamyxovirus and/or pneumovirus F proteins, or antigenic fragmentsthereof, comprise a polypeptide having at least 75%, 80%, 85%, 90%, 91%,92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity along its fulllength to an RSV F protein or mutant thereof selected from the groupconsisting of SEQ ID NO:53 and 61-64, wherein the polypeptide includesone or more of the following residues: 671, 149C, 458C, 46G, 465Q, 215P,92D, and 487Q.
 5. The nanostructure of claim 1, wherein the one or moreparamyxovirus and/or pneumovirus F proteins, or antigenic fragmentsthereof, comprise a polypeptide having at least 75%, 80%, 85%, 90%, 91%,92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity along its fulllength to an MPV F protein or mutant thereof selected from the groupconsisting of SEQ ID NO:65-68 and 101, wherein the polypeptide includesone or more of the following residues: 113C, 120C, 339C, 160F, 177L,185P, and 426C.
 6. The nanostructure of claim 1, wherein the firstpolypeptides and the second polypeptides comprise polypeptides having atleast 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%,or 100% identity along their full length to the amino acid sequencesselected from the following pairs: SEQ ID NO:1 and SEQ ID NO:2 (I53-34Aand I53-34B); SEQ ID NO:3 and SEQ ID NO:4 (I53-40A and I53-40B); SEQ IDNO:3 and SEQ ID NO:24 (I53-40A and I53-40B.1); SEQ ID NO:23 and SEQ IDNO:4 (I53-40A.1 and I53-40B); SEQ ID NO:35 and SEQ ID NO:36 (I53-40Agenus and I53-40B genus); SEQ ID NO:5 and SEQ ID NO:6 (I53-47A andI53-47B); SEQ ID NO:5 and SEQ ID NO:27 (I53-47A and I53-47B.1); SEQ IDNO:5 and SEQ ID NO:28 (I53-47A and I53-47B.1NegT2); SEQ ID NO:25 and SEQID NO:6 (I53-47A.1 and I53-47B); SEQ ID NO:25 and SEQ ID NO:27(I53-47A.1 and I53-47B.1); SEQ ID NO:25 and SEQ ID NO:28 (I53-47A.1 andI53-47B.1NegT2); SEQ ID NO:26 and SEQ ID NO:6 (I53-47A.1NegT2 andI53-47B); SEQ ID NO:26 and SEQ ID NO:27 (I53-47A.1NegT2 and I53-47B.1);SEQ ID NO:26 and SEQ ID NO:28 (I53-47A.1NegT2 and I53-47B.1NegT2); SEQID NO:37 and SEQ ID NO:38 (I53-47A genus and I53-47B genus); SEQ ID NO:7and SEQ ID NO:8 (I53-50A and I53-50B); SEQ ID NO:7 and SEQ ID NO:32(I53-50A and I53-50B.1); SEQ ID NO:7 and SEQ ID NO:33 (I53-50A andI53-50B.1NegT2); SEQ ID NO:7 and SEQ ID NO:34 (I53-50A andI53-50B.4PosT1); SEQ ID NO:29 and SEQ ID NO:8 (I53-50A.1 and I53-50B);SEQ ID NO:29 and SEQ ID NO:32 (I53-50A.1 and I53-50B.1); SEQ ID NO:29and SEQ ID NO:33 (I53-50A.1 and I53-50B.1NegT2); SEQ ID NO:29 and SEQ IDNO:34 (I53-50A.1 and I53-50B.4PosT1); SEQ ID NO:30 and SEQ ID NO:8(I53-50A.1NegT2 and I53-50B); SEQ ID NO:30 and SEQ ID NO:32(I53-50A.1NegT2 and I53-50B.1); SEQ ID NO:30 and SEQ ID NO:33(I53-50A.1NegT2 and I53-50B.1NegT2); SEQ ID NO:30 and SEQ ID NO:34(I53-50A.1NegT2 and I53-50B.4PosT1); SEQ ID NO:31 and SEQ ID NO:8(I53-50A.1PosT1 and I53-50B); SEQ ID NO:31 and SEQ ID NO:32(I53-50A.1PosT1 and I53-50B.1); SEQ ID NO:31 and SEQ ID NO:33(I53-50A.1PosT1 and I53-50B.1NegT2); SEQ ID NO:31 and SEQ ID NO:34(I53-50A.1PosT1 and I53-50B.4PosT1); SEQ ID NO:39 and SEQ ID NO:40(I53-50A genus and I53-50B genus); SEQ ID NO:9 and SEQ ID NO:10 (I53-51Aand I53-51B); SEQ ID NO:11 and SEQ ID NO:12 (I52-03A and I52-03B); SEQID NO:13 and SEQ ID NO:14 (I52-32A and I52-32B); SEQ ID NO:15 and SEQ IDNO:16 (I52-33A and I52-33B) SEQ ID NO:17 and SEQ ID NO:18 (I32-06A andI32-06B); SEQ ID NO:19 and SEQ ID NO:20 (I32-19A and I32-19B); SEQ IDNO:21 and SEQ ID NO:22 (I32-28A and I32-28B); SEQ ID NO:23 and SEQ IDNO:24 (I53-40A.1 and I53-40B.1); SEQ ID NO:41 and SEQ ID NO:42 (T32-28Aand T32-28B); SEQ ID NO:43 and SEQ ID NO:44 (T33-09A and T33-09B); SEQID NO:45 and SEQ ID NO:46 (T33-15A and T33-15B); SEQ ID NO:47 and SEQ IDNO:48 (T33-21A and T33-21B); SEQ ID NO:49 and SEQ ID NO:50 (T33-28A andT32-28B); and SEQ ID NO:51 and SEQ ID NO:44 (T33-31B and T33-09B (alsoreferred to as T33-31B)) 7.-8. (canceled)
 9. The nanostructure of claim1, wherein the first polypeptides comprise polypeptides having at least75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%identity along their full length to the amino acid sequence selectedfrom the group consisting of I53-50A (SEQ ID NO:7), I53-50A.1 (SEQ IDNO:29), I53-50A.1NegT2 (SEQ ID NO:30), and I53-50A.1PosT1 (SEQ IDNO:31), and the second polypeptides comprise polypeptides having atleast 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%,or 100% identity along their full length to the amino acid sequenceselected from the group consisting of I53-50B (SEQ ID NO:8), I53-50B.1(SEQ ID NO:32), I53-50B.1NegT2 (SEQ ID NO:33), and I53-50B.4PosT1 (SEQID NO:34).
 10. (canceled)
 11. The nanostructure of claim 1, wherein theone or more paramyxovirus and/or pneumovirus F proteins, or antigenicfragments thereof, are expressed as a fusion protein with the firstpolypeptides. 12.-15. (canceled)
 16. The nanostructure of claim 1,wherein the one or more paramyxovirus and/or pneumovirus F proteins, orantigenic fragments thereof comprises polypeptides having at least 75%,80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%identity along their full length to the amino acid sequence the aminoacid sequence of DS-Cav1 (SEQ ID NO:53).
 17. The nanostructure of claim11, wherein each fusion protein comprises an amino acid linkerpositioned between the first polypeptide and the one or moreparamyxovirus and/or pneumovirus F proteins, or antigenic fragmentthereof.
 18. The nanostructure of claim 17, wherein the amino acidlinker sequence comprises one or more trimerization domain.
 19. Thenanostructure of claim 17, wherein the amino acid linker sequencecomprises the amino acid sequence GYIPEAPRDGQAYVRKDGEWVLLSTFL (SEQ IDNO:54).
 20. The nanostructure of claim 17, wherein the amino acid linkersequence comprises a Gly-Ser linker.
 21. The nanostructure of claim 11,wherein the fusion protein comprises polypeptides having at least 75%,80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%identity along their full length to the amino acid sequence selectedfrom the group consisting of SEQ ID NOS:69-100.
 22. The nanostructure ofclaim 21, wherein: (a) when each fusion protein isDS-Cav1-foldon-T33-31A (SEQ ID NO:69) or DS-Cav1-T33-31A (SEQ ID NO:70),each second polypeptide is T33-31B (SEQ ID NO:44); (b) when each fusionprotein is DS-Cav1-foldon-T33-15B (SEQ ID NO:71) or DS-Cav1-T33-15B (SEQID NO:72), each second polypeptide is T33-15A (SEQ ID NO:45); (c) wheneach fusion protein is DS-Cav1-foldon-I53-50A (SEQ ID NO:73) orDS-Cav1-I53-50A (SEQ ID NO:74), each second polypeptide is I53-50B (SEQID NO:8), I53-50B.1 (SEQ ID NO:32), I53-50B.1NegT2 (SEQ ID NO:33), orI53-50B.4PosT1 (SEQ ID NO:34); or (d) when each fusion protein isDS-Cav1-I32-28A (SEQ ID NO:75), each second polypeptide is I32-28B (SEQID NO:22).
 23. The nanostructure of claim 16, wherein each firstpolypeptide comprises a fusion protein of DS-Cav1 (SEQ ID NO:53) linkedto SEQ ID NO:7 (I53-50A) via an amino acid linker. 24.-26. (canceled)27. The nanostructure of claim 23, wherein each second polypeptidecomprises the amino acid sequence selected from the group consisting ofI53-50B (SEQ ID NO:8), I53-50B.1 (SEQ ID NO:32), I53-50B.1NegT2 (SEQ IDNO:33), or I53-50B.4PosT1 (SEQ ID NO:34).
 28. The nanostructure of claim23, wherein each second polypeptide comprises the amino acid sequence ofI53-50B.4PosT1 (SEQ ID NO:34).
 29. The nanostructure of claim 1, whereinthe nanostructure: (a) binds prefusion F-specific antibodies includingbut not limited to monoclonal antibody 25; (b) forms a symmetricalstructure, including but not limited to an icosahedral structure; (c) isstable at 50° C.; and/or (d) is stable in 2.25M guanidine hydrochloride.30. A recombinant nucleic acid encoding the first polypeptide fusionprotein as recited in claim
 1. 31. (canceled)
 32. A recombinant hostcell, comprising the recombinant nucleic acid of claim
 30. 33.(canceled)
 34. An immunogenic composition comprising the nanostructureof claim 1, and a pharmaceutically acceptable carrier.
 35. Theimmunogenic composition of claim 34, further comprising an adjuvant. 36.A method for generating an immune response to paramyxovirus and/orpneumovirus F protein in a subject, comprising administering to thesubject in need thereof an effective amount of the nanostructure ofclaim 1 to generate the immune response.
 37. A method for treating orlimiting a paramyxovirus and/or pneumovirus infection in a subject,comprising administering to the subject in need thereof an effectiveamount of the nanostructure of claim 1 to, thereby treating orpreventing paramyxovirus and/or pneumovirus infection in the subject.38. The method of claim 36, wherein the administering results inproduction of paramyxovirus and/or pneumovirus neutralizing antibodiesin the subject.
 39. The method of claim 38, wherein the neutralizingantibodies are present in sera of the subject at a titer (1/ID₅₀) of atleast 9,400.
 40. A process for assembling the nanostructures of claim 1in vitro, comprising mixing two or more nanostructure components inaqueous conditions to drive spontaneous assembly of the desirednanostructure. 41.-43. (canceled)